WO2018103977A1

WO2018103977A1 - Delivery of media content

Info

Publication number: WO2018103977A1
Application number: PCT/EP2017/078488
Authority: WO
Inventors: Paul DEANS; Simon BEDDUS
Original assignee: British Telecommunications Public Limited Company
Priority date: 2016-12-06
Filing date: 2017-11-07
Publication date: 2018-06-14

Abstract

Media content is delivered from a content delivery system (6,9) to a terminal (17) associated with a user. The content delivery system maintains a store (14) of media data to be delivered to the user when a mobile communications device (1) associated with the user transmits a signal (41) indicative that the user is able to receive the media data. During display of the media data by the output device, the device transmits data (59) to the content delivery system responsive to user activity to record delivery of the media data in a user profile (10), indicative that the content has been viewed. The activity data may be detection of movement of the user terminal, eye-tracking, face recognition, or a response to a prompt in the media content. In one embodiment, a mobile communications device (1b) transmits a beacon signal and is detected by a sensor (23) at a location associated with a viewing apparatus (17), and the location of the device is recorded in a data store associated with the monitoring system. The location is compared with locations of other devices (20) requiring data content of a predetermined category, and if the number of communications devices recorded in the store as belonging to a set and having a matching location attains a predetermined threshold, the required data content is sent to the viewing apparatus (17).

Description

Delivery of Media Content

This invention relates to a media streaming system, that is to say apparatus which causes a data stream to be transmitted from a content delivery server to a client device for delivery to a terminal device having a user interface to allow a user to view and listen to audio-visual content coded in the data stream. (For brevity, the term "viewing" will be used in this specification to embrace any form of delivery of media content to the end user, including text, (e.g subtitles), audio and haptic, whether or not there is a visual element to the content.

The present invention is of application in a number of contexts such as distance learning and in entertainment funded by advertising. In these fields, viewers of content may wish to view content in a different order to that in which it has been compiled by the content provider, or to postpone viewing parts of it. They may also be more interested in some parts of the content than in others. However, in many cases the content providers often have a requirement that the content, or some particular parts of it, be viewed, and require confirmation that this has taken place. If content display can be deferred to a later time, many users would choose a time and place when there is no-one available to view it, for example in the middle of the night.

It is known, for example from US2013/165151 , to arrange delivery of data to a user device at a time when the user is expected to be able to view it. However, it is nevertheless desirable for the supplier of media content to ensure that the content has actually been viewed by the user and not, for example, delivered to and displayed on a device which is unobserved or unattended.

According to a first aspect of the present invention, there is provided a method of delivering media content from a content delivery system to a user, wherein:

the content delivery system maintains a store of media data to be delivered to the user; a signal is transmitted to the content delivery system by a mobile communications device associated with the user indicative that the user is able to receive the media data;

in response to the signal, the content delivery system transmits media data to an output device for display; a communications device associated with the user monitors activities of the user during display of the media data by the output device and transmits activity data to the content delivery system in response to such user activity;

and the content delivery system updates the store to record delivery of the media data in response to predetermined activity data being reported to the content delivery system.

According to another aspect, a content delivery system is provided comprising a store of media data for delivery to users, a content server for transmitting media data to one or more output devices for display, a user monitoring system for receiving activity data relating to users to whom the media data is to be delivered, wherein the content delivery system is configured to detect an input indicative that a user is able to receive the media data, to deliver the media data to an output address associated with the user, and to update the store to record delivery of the media data in response to predetermined activity data being reported to the user monitoring system.

The output device may be a separate device independently connected to the content delivery system, or it may be integrated into the communications device. In the latter case, the integrated output and communications device may be arranged to detect body position and movement of the user to determine whether the user is viewing content being displayed. A heuristic process may be used to determine positions and visual inputs of the device which correspond to a user viewing content on the device. If the output device and the communications device are separate, delivery of media data to an output device may be prompted by detection of one or more communications devices in proximity to the output device which are identified as belonging to a predetermined set of communications devices, and for which data content of a predetermined category is to be delivered to all members of the set, and if the number of communications devices recorded in the store as belonging to a set and having a matching location attains a predetermined threshold, the data content is delivered to the output device associated with that location. If there are two or more such sets, prioritisation of which data is to be transmitted may be selected by criteria such as the size of the set (number of members), the length of time since individual devices have been added to the set, or by commercial criteria.

A message may be sent to one or more of the communications devices in the set and identified as being in the location associated with the output device to alert users of the mobile communications devices to the output device. On receipt by the monitoring system of a viewing report from a communications device, the communications device can be deleted from the set of communications devices having the requirement for the data content. The activity data transmitted to the content delivery server may be a signal generated in response to a user activity prompted by display of content on the output device, the content delivery system updating the store to record delivery of the media data in response to predetermined activity data being reported to the content delivery system within a predetermined time after display of the content. The activity data may include any or all of an audio input processed by a speech recognition system, a visual image of the output device taken by a camera installed in the user device, and detection of body position and movement of the user by the communications device. The content delivery system may includes a heuristic analysis process to identify activity indicative that the user has been viewing the media data.

The invention may be embodied in a processor and memory storing computer program code for performing the process, and in program code arranged such that when loaded into a computer system and executed thereon, cause the computer to perform the method.

Embodiments of the present invention are concerned with a delivery system arranged to enable users to view some parts of media content and postpone the viewing of other parts to a more convenient time. For example, in distance learning, it may be inconvenient for the viewer to take a comprehension test on the same device as that on which the content was viewed. Another example is a desire to view entertainment content without interruption by advertising content. However, in both cases, the content provider will wish the deferred content to be viewed eventually. Despite the best efforts of the advertising industry to make it entertaining, advertising content is often unpopular with viewers, and most users attempt to skip t, for example by "fast-forwarding" so that they can watch the content in between the advertisements. If advertising content cannot be skipped or removed from view, it is seen as a nuisance, interrupting the flow of the content and wasting the viewer's time. Whether the advertising content is placed before the content, interrupting the content, super-imposed over content, or around content, it is disliked by users as being intrusive and distracting from the desired content. No vendor or distributor wants their product (or service) associated with such nuisance. However, it has to be recognised that the commercial purpose of any free (non-subscription) media content is to expose advertising content to viewers (or to deliver viewers to the advertisers) and without advertising content, free-to-air media services would be uneconomic and most media content would be unavailable except on subscription - a business model which is also unpopular with viewers. It is relatively straightforward to ensure that required content is delivered and played. However, a well-known problem for advertisers is that there may be no-one actually viewing the content as it is played. Even in live content (which cannot be fast-forwarded), advertisement breaks are commonly used by viewers as an opportunity to leave the room for one reason or another. (It is well-known that utility companies, particularly electricity and water, experience surges in demand when commercial breaks occur in popular television shows).

It is known to provide interactive advertising content, for example US8246454 (Sony), in which the advertising content is modified - for example shortened - if a viewer performs a predetermined action. However, this does not ensure that the content is viewed.

Embodiments of the present invention are intended to enable the viewer to have more control over how and when different elements of the content are viewed, whilst still ensuring that certain content is not ignored. If the user does not wish the desired content to be interrupted by advertising, he may wish to select an alternative time and place at which it would be more suitable and convenient for the user to view that content. From the user's point of view, the optimum time and place would usually be an indefinite time in the far future (effectively "never"), but from the advertiser's point of view this would obviously be unacceptable, and no advertiser would pay a content delivery service to allow their content to be treated in that way. It is therefore desirable to be able to prove that individuals honour their commitment to have the content displayed at a later time, and to view it, or to put them in a situation where they are more likely to view the content.

There can also be situations in which the content provider would prefer the advertising content to be deferred. For example, smartphone screens can be too small to get the user's attention, so a content provider may prefer to deliver the requested content at the time it is requested, but arrange for associated advertising content to be displayed on a larger screen at a later time. This system increases the relevance of user profiling by creating it from both manual and automatic means. Manual updates, direct from the user, allow a user's comfort level for intrusion to be provided for and an automatic update (which includes their whereabouts) is recorded, whilst providing confirmation that the content has been viewed.

Although the embodiments will be particularly described in relation to advertising content, it will be recognised that it may be applicable to any content which has an "information" or "entertainment" element and a "required" element, and may have application for example in the fields of education and training. For example, many structured on-line training systems include a test element, and are often arranged such that the user must pass each test before moving on to the next section. This can be unduly prescriptive - the user may, for example, be viewing the training content on equipment not equipped for the inputs required for the test element - for example the user may be driving whilst listening to training content in audio format. The user may wish to study the subject in more detail before taking the test element.

An embodiment of the invention will now be described with reference to the drawings, in which:

Figure 1 depicts a system according to the invention depicting the entities which cooperate to perform the embodiment;

Figure 2 depicts a user presence detection system forming part of the embodiment;

Figure 3 depicts a process for identifying when users having related profiles are in the vicinity of a playback device

Figure 4 depicts a user activity processor forming part of the embodiment.

Figure 5 is a block diagram of a computer system suitable for operating embodiments of the invention.

The Figures illustrate the functional elements which co-operate to perform the invention. These may be implemented in software on a general-purpose computer or a distributed system. Functions implemented on the user device may be installed in firmware or by downloading applications to the user device from a remote application store.

Referring first to Figure 5, a computer system 100 comprises a central processor unit

(CPU) 6 is communicatively connected to a data store 104 and an input/output (I/O) interface 106 via a data bus 108. The data store 104 can be any read/write storage device or combination of devices such as a random access memory (RAM) or a non-volatile storage device, and can be used for storing executable and/or non-executable data. Examples of non-volatile storage devices include disk or tape storage devices. In this embodiment a number of different of data 5, 10, 1 1 , 12, 36 are stored. Further data may be retrievable from remote storage facilities. The I/O interface 106 is an interface to devices for the input or output of data, or for both input and output of data. Examples of I/O devices connectable to I/O interface 106 include a keyboard, a mouse, a display (such as a monitor) and a network connection 3. Such a computer system can be used to operate embodiments of the invention, as will now be described.

Figure 1 depicts such a computer system 100 configured to operate as a content distribution system 100, in co-operation with an Internet Server provider (ISP) network 2 to which user devices 1 a, 1 b may be connected, and a remote network 15 to which the same or another user device 1 b may be connected. All the systems are connected through a data network 3, such as the Internet.

The content distribution system 100 will now be discussed in more detail. The central processor 6 hosting a number of other functions which may be co-located or distributed. Such functions include an authentication server 4 to validate access to the system by individual users, having access to a user register 5 recording user data, an interface 7 operating on SMTP (Simple Mail Transfer Protocol), SMS and user generic messaging protocols such as XMPP to co-ordinate interactions between the content distribution system 100 and the data network 3, and a user co-ordination processor 8 configured to identify users in proximity to each other which have similar profiles to each other. The operation of this processor will be discussed in more detail later.

A content server 9 is arranged to receive content requests from the user 1 by way of the data network 3 and retrieve the required content data from a content store 14. This process is mediated by the central processor in accordance with user profile data 10, 1 1 , 12 relating to the user making the request. The system also operates an application store 13, storing downloadable application software 25 for installing on client devices.

The remote network 15 is depicted as providing connections to various types of user terminal, including "smart watches" 16, electronic billboards 17, and flatscreen television sets. The network is also connected to one or more activity sensors 19 associated with the user terminals, and capable of monitoring for human activity such as eye movement in the vicinity of the activity sensor and therefore of the terminal 16, 17, 18. A second user device 20 is depicted communicating with the remote network 15. This device, and the first user device 1 b, are both equipped with respective beacons 22, 23 to allow their presence to be detected by a sensor 21 associated with an aggregator 26 connected to the remote network 15.

The content distribution system also provides a webpage server 24 for delivering instruction data to users to configure their respective user profiles 10, 1 1 , 12 to operate in a way appropriate to their circumstances.

A user profile generation processor 27 is provided which generates metadata which represents viewers' habits and the content delivered to the user. Such processing is similar in principle to that used by online shopping services to identify users' shopping interests from their browsing activities.

A user activity processor 38 monitors user activity to establish if content has been viewed by a user. The processor in this embodiment is a heuristic system, using machine learning to operate in a training phase and then an in-life phase.

The embodiment operates as follows. In an initial Registration step, the user browses to a registration webpage using a user terminal 1 a or 1 b. The webpage is served from the webpage server 24 via the internet 3 and ISP network 2 to the user device 1 a or 1 b, and registers interest in the scheme via a webpage form using ISP network 2, Internet 3, the Control code embodied in the central processor 6, the authentication server 4 and the User Register 5. Registration would include the user's e-mail address and login details (username and password). An e-mail acknowledgement is generated by the SMTP messaging server 7 and transmitted to the user device 1 a/1 b via the Internet 3 and ISP network 2.

In the next stage, the user is required to create a profile 10, which contains (amongst other things) device information, privacy comfort level, known availability times when content can be viewed, etc. This is initiated from the user device 1 a/1 b via the ISP network 2 and internet 3, central processor 6 to the user profile 10. Acknowledgement occurs via the same route in reverse.

In the next step the User is required to download an application 25 from the application store 13, by using the device 1 b via the ISP network 2, internet 3 and application 25 store 13 (having first navigated to the application 25 store and searched for it). The application store 13 can be a webpage containing a download URL or a commercial application 25 store.

Once downloaded onto the device 1 b, the user installs the application 25. Once installed, it triggers the central processor 6 to register with the User Register 5 that user 1 has downloaded the application 25, and enables the beacon 23.

The user may be allowed to choose a level of intrusion with which they feel comfortable.

Having registered on the system, agreed to a certain level of intrusion, downloaded the application 25 and run it, the user can now receive content (audio or video) without having to experience adverts before, between, or superimposed on, the audio or video content, the user having accepted a requirement to view them later.

To view content, the User logs in using the device 1 a or 1 b and downloads content for viewing, using login details provided during registration. The login path is via device 1 a or 1 b, ISP network 2, Internet 3, and central processor 6 to the authentication server 4. If the credentials are accepted, the user can receive the content.

The profile may be automatically updated in order to record and gain insight into viewing habits so that appropriate content from a cache 14 can be pushed to the user, or to gain insight into the user whereabouts so that appropriate content can be sent at an appropriate location or at an appropriate time. The user's viewing habits are captured and analysed by central processor 6 and the user profile generation processor 27 which filters and updates the user 1 profile with filtered output (representing the user's browsing history viewing habits and content consumed). An example of such input is included in Table 1 below.

Content ID VID0001 VID0002 VID0003 VID0004

URL http// http// http// http//

Duration 3m 52s 04:18 12:37 08:54

Spring Watch Alan Flirts With Mobile How to Use

Title Series 1 Jill - I'm Alan phone a Tablet

Episode 3 Partridge - BBC review Part 1

Content Android Photoshop

BBC BBC

Owner Authority Tutor

Tags tag data 1 tag data 2 tag data 3 tag data 4

Device Type Acme 123 Acme 123 Acme 123 Acme 123 01/1 1/2003 01/1 1/2003 01/1 1/2004 01/1 1/2004

Timestamp

17:04 18:44 13:53 15:44

Table 1 : Example of user profile data

When the beacon 23 is detected by a network 2, 15, the profile 10 is updated with the latest known whereabouts of the user. This could be in the form of GPS co-ordinates or cellular network identifier (from mobile network components) or just a known location. Such beacon information can be polled or pushed at intervals. For pushing, the Application 25 uses information from the beacon 23 and can push location information (via the remote ISP network 15 or local ISP network 2 via the internet 3) to the central processor 6 then into the user profile 10. For polling, the central processor 6 polls the application 25, which interrogates the beacon 23. The polling is via the ISP network 15, or the local ISP network 2 via the internet 3, to update the user profile 10.

A prompt may be generated in response to an action by the user to confirm that the device is in use. This may be the result of a prompt generated by deliberate action of the user, or generated automatically if the device detects it is being handled.

Referring now to Figure 2, which depicts a user presence detection system, when a user device 1 b enters a zone 200 which contains one or more sensors 21 , the sensor 21 detects the beacon signal 23 transmitted by the user device 1 b. The sensor 21 sends user 1 data via an Aggregator 26, remote ISP network 15, and Internet 3 to the central processor 6. The central processor 6 instructs the content server 9 to retrieve content from the content store 14 and forward it to the most appropriate device, which could be all, some or one of the user's device 1 b, a smart watch 16, an electronic billboard 17, a flat screen device 18, or another user device.

If a billboard 17 or flat screen 18 is the chosen device, the user co-ordination processor 8 can be used to establish if there is more than one user with a similar profile in the vicinity. If so, an advert can be pushed at a device 17, 18 in close proximity with both users, thus exploiting their shared locale. Normally billboards show an advert which might only have a small chance of interesting a user, but this allows content to be shown that is known to be relevant to users, by reference to the users' respective profiles. If the user co-ordination processor 8 establishes that that two or more users in the vicinity may have similar interests (i.e. similar profiles) it can arrange to show content relevant to all those users in an efficient manner. The operation of the User co-ordination processor 8 is depicted in Figures 2 and 3. Each billboard 17 or similar display device has an associated beacon detector 21 which has an associated detection zone 200 within which a beacon 22 transmitted by a user device 1 b can be detected. Each billboard also has an associated area 170 within which content it is displaying can be viewed. The detection zone 200 and content viewing area 170 should be arranged to be as close to coterminous as possible, to ensure that the content displayed by the billboard device 17 can be viewed by any user whose beacon 22 is detected by the billboard's associated sensor 21 .

The User co-ordination processor 8 first establishes if there is more than one user with a similar profile in the vicinity. To do this, it identifies any user beacons 22 and 23 that are detected by the detection sensor 21 , and then accesses the user profiles 10, 1 1 associated with those beacons. Such information is aggregated, and the user profiles are updated so that they contain the latest whereabouts of the respective users.

An example of a workflow which initiates the identification of similarly profiled users is depicted in Figure 3

When a User terminal 1 enters the detection zone 200 of a sensor 21 , the sensor detects the beacon of the terminal (step 41 ) and transmits an alert (42) to the central processor 6 (by way of the aggregator 26, Remote ISP Network 1 and Internet 3, as shown in more detail in Figure 4) to indicate that the user terminal 1 has entered its detection zone 200. The alert 41 includes an identification code (user ID) for the sensor 21 . At this point, the central processor 6 determines if there are two or more users in the vicinity with similar profiles. The processor determines which of several contents available in the content store 14 should be delivered to the billboard 17, by reference to the profiles of the users in its detection zone 200. The central processor then forwards this data to the co-ordination processor 8, (step 43) which updates the user profile 10 relating to the user terminal 1 b that has been detected (step 44), and then retrieves all user profiles (10, 1 1 ,12) currently associated with the sensor 21 (step 45).

The co-ordination processor 8 next compares these profiles for similarities and returns a result to the central processor (step 46). The Central processor 6 then selects content matching the common aspects of the profiles 10, 1 1 , 12 The process may be configured to select content that matches the maximum number of user profiles, but other criteria may be used such as the length of time that has elapsed for individual users since they have received requested content. The central processor instructs the content server 9 (step 47) to retrieve the selected content from the content store 14 (step 48) and forward it to the electronic billboard 17 or other display device (step 49). The content may be further tailored to the individual users in order to attract their attention, for example by addressing them by name. Alternatively, an alert (50) may be sent to the user's portable terminal 1 drawing their attention to the display device 17.

At this point two or more users in the vicinity of the billboard 17 will therefore have content played to them which has a relevance to them both. This system employs advertising 'space' more efficiently, in that it pushes an advert to a locale, which contains more than one user - and is relevant to all those users' profiles. That is, two or more profiles are compared for similarities and content can be selected based on those similarities.

In order to determine whether the users have actually viewed the content, one or more sensors 19 are provided. These may be on board the user device 1 or in the vicinity of the display device 17, 18. The sensor 19 transmits data to the User activity processor 38 to determine whether individual users viewed the content transmitted to them. This may be achieved as follows, and as depicted in Figure 4.

Several typical functions available on modern communications devices such as smartphones may be used to monitor user activity. These include face detection, eye-tracking, head tilt recognition, viewing angle, voice-directed confirmation, button pressed confirmation and orientation detection. These can be used to determine whether the user has indeed viewed content displayed, either on the device 1 b itself, or on a related device such as an electronic billboard 17 or other display 18.

For this type of sensing, the content can be played at a known time, co-ordinating with an internal clock on the user device 1 b. This process will be described with reference to Figure 4, which depicts the user activity processor 38 of Figure 1 in more detail.

The Central processor 6 registers data from each user device 1 b onto a database 36, which is used by the user activity processor 38 to return a message 59 to the Central processor 6b indicating whether the required content has been viewed, in order to update the relevant user profile 10.

The operation of the processor 38 has a training phase, involving interactions shown by arrows 51 -54, and an in-life phase (arrows 55-58). During the training phase (steps 51 -54), the Training Adaptor 37 takes information from the database 36 relating to the user terminals (step 51 ) and enters them into the pre-classifier 28 (step 52). The pre-classifier 28 creates a table (29) to be read by the classifier 30 (step 53). The classifier 30 uses linear regression techniques to create a model 31 (step 54), such as a decision tree.

The cues which identify whether the user is indeed viewing the content may include detection of any of the following events, or a combination of them. Some of these events are appropriate to detection of viewing content on the device itself, and others for reporting that content has been viewed on another device such as an electronic billboard.

An eye-tracking application may run on the user device 1 b, using a smartphone's inbuilt camera to detect, using pattern recognition software, whether a user is looking at the screen. Pattern recognition may also be used for movement detection, to determine if the user's head has moved during the playback of the content, and thus that the eyes detected seen by the eye- tracking processor are part of a real person and not, for example, a photograph. The application may also report the orientation of the device itself, specifically at an appropriate angle for viewing the content (and not, for example, face down on a table).

If eye tracking and head tilt are not available, for example when the content is displayed on a separate display device such as a billboard 17, a photograph of the display may be taken by the user using the device's camera, or a code word or QR code could be displayed.

The user device may also be arranged to detect a response to the content, for example a voice input or a button press, during display of the content, and/or within a predetermined interval after the end of the content, to confirm that the user has been present during playback and has not simply left the device with the content running.

Classified behaviour (or predictions) in the form of a tree or model 31 can also be refined using metadata from human analysis, annotation interviews, etc. In doing so, clustered values can be associated with context, such as the user lying down, viewing in landscape mode, device in user's pocket, mobile device fixed in holder in car, user at a desk or table, etc.

During the in-life phase (steps (55-58), the in-life adaptor 32 retrieves information from the database 36 (step 55). This information represents a single set of values from a device 1 b (i.e. statistics for eye-tracking, head tilt, viewing angle (pitch, yaw, roll max/mins) etc. These values are sent into a pre-classifier 33 (step 56) which turns them into data strings (34).

The comparator 35 takes each string 34 (step 57) and compares them with a model 31 (a table, tree, etc. (step 58) and sends a message to the central processor 6 (step 59). This message states whether the video is predicted to have been seen or not. When the message 59 is received by the central processor 6, it updates the user profile 10 (step 599) to confirm that the user has given the required response to the content. The user profile 10 can be accessed by the central processor 6 when the user requests new content from the content store 14 to determine whether the previously required content has been viewed, and from that to determine whether access to further content should be permitted. The actions to be taken if the required content has not been accessed may include barring access to free content until the user has viewed the required advertising or other compulsory content. This may be done either by barring access altogether, or by requiring a subscription to be paid.

Claims

1 . A method of delivering media content from a content delivery system to a user, wherein:

the content delivery system maintains a store of media data to be delivered to the user;

a signal is transmitted to the content delivery system by a mobile communications device associated with the user indicative that the user is able to receive the media data; in response to the signal, the content delivery system transmits media data to an output device for display;

a communications device associated with the user monitors activities of the user during display of the media data by the output device and transmits activity data to the content delivery system in response to such user activity;

2. A method according to Claim 1 , wherein the output device is integrated into the communications device.

3. A method according to claim 2, wherein the integrated output and communications device detects body position and movement of the user to determine whether the user is viewing content being displayed.

4. A method according to Claim 3, wherein the communications device uses a heuristic process to determine positions and visual inputs of the device which correspond to a user viewing content on the device.

5. A method according to Claim 1 , wherein the output device and the communications device are separate, delivery of media data to the output device being prompted by detection of the communications device in proximity to the output device

6. A method according to Claim 5, comprising the steps of

detecting the presence of a communications device transmitting a beacon signal (41 ) within range of a sensor at a location associated with the output device;

transmitting a signal (42) from the sensor to a monitoring system, the signal being indicative of the presence of the communications device at the location;

recording (44), in a data store associated with the monitoring system, the location of the communications device detected by the sensor ;

comparing (45) the location of the communications device recorded in the store with locations of one or more other recording devices recorded as belonging to a predetermined set of communications devices;

identifying (46) communications devices having matching locations;

if the number of communications devices recorded in the store as belonging to a set and having a matching location attains a predetermined threshold, delivering data content

(49) to the output device associated with that location.

7. A method according to Claim 6, in which a message is sent to one or more of the communications devices in the set and identified as being in the location associated with the output device to alert users of the mobile communications devices to the output device.

8. A method according to Claim 6 or Claim 7, in which a set of two or more communications devices is defined to exist if a requirement is recorded in the data store that data content of a predetermined category be delivered to all members of the set of mobile communications devices.

9. A method according to Claim 6, Claim 7 or Claim 8, in which, on receipt by the monitoring system of a viewing report from a communications device, the communications device is deleted from the set of communications devices having the requirement for the data content.

10. A method according to Claim 6, Claim 7, Claim 8 or Claim 9 in which, if two or more sets of communications devices are identified as having the same location, data content is selected for transmission to the output device according to the respective sizes of the sets of communications devices.

1 1 . A method according to Claim 6, Claim 7, Claim 8 or Claim 9 in which a time is recorded at which a member of a set joined that set, and if two or more sets of communications devices are identified as having the same location, data content is selected for transmission according to the time stamp data recorded for the members of each set.

12. A method according to any preceding claim, in which the activity data transmitted to the content delivery server is a signal generated in response to a user activity prompted by display of content on the output device.

13. A method according to Claim 12, wherein the content delivery system updates the store to record delivery of the media data in response to predetermined activity data being reported to the content delivery system within a predetermined time after display of the content.

14. A method according to Claim 12 or Claim 13, wherein the activity data is an audio input processed by a speech recognition system.

15. A method according to Claim 12 or Claim 13, wherein the activity data is a visual image of the output device taken by a camera installed in the user device.

16. A content delivery system, comprising a store of media data for delivery to users, a content server for transmitting media data to one or more output devices for display, a user monitoring system for receiving activity data relating to users to whom the media data is to be delivered, wherein the content delivery system is configured to detect an input indicative that a user is able to receive the media data, to deliver the media data to an output address associated with the user, and to update the store to record delivery of the media data in response to predetermined activity data being reported to the user monitoring system.

17. A content delivery system according to Claim 16, wherein the predetermined activity data includes a predetermined time after display of the content.

18. A content delivery system according to Claim 16 or Claim 17, wherein the predetermined activity data is an audio input and the content delivery system comprises a speech recognition system for analysing the audio input.

19. A content delivery system according to Claim 16 or Claim 17, wherein the predetermined activity data is a visual input and the content delivery system comprises a pattern recognition system for analysing the visual input.

20. A content delivery system according to Claim 16 or Claim 17, wherein the predetermined activity data relates to body position and movement of the user detected by a communications device, and the content delivery system includes a heuristic analysis process to identify activity indicative that the user has been viewing the media data.

21 . A content delivery system according to any of claims 16 to 20, comprising:

sensing apparatus (21 , 26) for detecting the presence of a communications device transmitting a beacon signal 41 within range of a sensor (21 ) at a location associated with the output device (17)

a monitoring system (6) for recording, in a data store (10, 1 1 , 12) associated with the monitoring system, the location of the communications device detected by the sensing apparatus

a co-ordination processor (8) for comparing the recorded location of the communications device recorded in the store (10, 1 1 , 12) with locations of one or more other communications devices recorded as belonging to a predetermined set of communications devices, and identifying sets of communications devices having a matching location,

a data delivery system (9, 14) responsive to the co-ordination processor to deliver content to the output device (17) associated with that location.

22. A content delivery system according to Claim 21 , further comprising a message generation system for generating a message to be transmitted to one or more of the communications devices in the set and identified as being in the location associated with the output device, to alert users of the communications devices to the output device.

23. A content delivery system according to Claim 21 or Claim 22 further comprising a user profiling system (27) for receiving data relating to a plurality of communications devices (1 a, 1 b), and recording the data in the data store, the data store being arranged to define a set of two or more communications devices if a requirement is recorded in the data store (10, 1 1 , 12) that data content of a predetermined category be delivered to all members of the set of communications devices.

24. A content delivery system according to Claim 21 or Claim 22, in which the user profiling system is arranged to receive data viewing reports from communications devices, and to delete communications devices from sets recorded in the store in response to the data viewing reports.

25. A computer system including a processor and memory storing computer program code for performing the steps of any of Claims 1 to 15.

26. A computer program element comprising computer program code to, when loaded into a computer system and executed thereon, cause the computer to perform the steps of a method as claimed in any of Claims 1 to 15.