Patent Publication Number: US-2012047033-A1

Title: System, method and computer readable medium for placing advertisements into web pages

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of and claims priority from U.S. patent application Ser. No. 12/435,770 filed on May 5, 2009, entitled SYSTEM, METHOD AND COMPUTER READABLE MEDIUM FOR PLACING ADVERTISEMENTS INTO WEB PAGES; this application is incorporated herein by reference in its&#39; entirety. 
    
    
     FIELD OF THE INVENTION 
     This disclosure relates to a system, method and computer readable medium for placing advertisements into web pages. 
     BACKGROUND OF THE INVENTION 
     The performance or effectiveness of ads dynamically placed within a web page is typically measured using clickstream data. In a performance based method, when a user clicks on an ad, a URL resource for the ad web page is fetched and loaded into the client browser. Simultaneously, a statistic is updated to increase the relevance of that ad within the context, i.e. within the original web page. An alternative, content matching solution for measuring ad effectiveness uses keywords. A user wishing to place an ad enters keywords or keywords are extracted from an ad&#39;s text and used to perform relevance matching to the words within a web page. Both performance based and content matching methods may be combined to select ads that are relevant to the content and that have performed statistically well in similar contexts. 
     A problem with these existing methods is that they rely on click stream data which is typically coarse grained. A further problem is that these solutions tend to treat all words within the web page substantially the same, regardless of where in the web page the content appears. 
     What is required is a system, method and computer readable medium for selecting advertisements that makes use of how the attention of a user is directed on the web page. 
     SUMMARY OF THE INVENTION 
     In one aspect of the disclosure, there is provided a method for placing an advertisement into a web page comprising a plurality of content elements. The method comprises determining a plurality of candidate advertisements, retrieving attention data in respect of the content elements of the web page, using the attention data to select an advertisement from the candidate advertisements, and placing the selected advertisement into the web page. 
     In one aspect of the disclosure, there is provided an ad server for placing advertisements into a web page. The ad server comprises an ad data store that stores a plurality of ads, and an ad server processing module. The ad server processing module is configured to receive an ad request in respect of a URL, determine a set of candidate advertisements from the ad store, retrieve ad performance statistics from the ad data store for the candidate advertisements, and select an advertisement for the ad request using the ad performance statistics. The ad performance statistics comprise a plurality of attention events, each attention event indicating an element of a web page corresponding to the URL as a source element and a candidate advertisement as a destination element. 
     In one aspect of the disclosure, there is provided a computer-readable medium comprising computer-executable instructions for execution by a processor, that, when executed, cause the processor to receive an advertisement placement request in respect of a URL, determine a document object model of a web page corresponding to the URL, determine a plurality of document object model elements of the URL, retrieve an attention ranking of the document object model elements, determine a plurality of candidate advertisements, determine a relevance score for each candidate advertisement, and select an advertisement from the plurality of candidate advertisements dependent on the relevance scores. Determining the relevance score comprises determining a content matching factor dependent on a match of the content of the advertisement to the content of a document object model element, and weighting the content matching factor dependent on the rank of the respective document object model element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will now be made, by way of example only, to specific embodiments and to the accompanying drawings in which: 
         FIG. 1  illustrates an ad placement system; 
         FIG. 2  illustrates a method for placing advertisements into a web page; 
         FIG. 3  illustrates a system for determining attention areas for a web page interaction; 
         FIG. 4  illustrates an example of an event header message; 
         FIG. 5  illustrates an example of an event stream message; 
         FIG. 6  illustrates an operation of a layout module; 
         FIG. 7  illustrates an operation of an attention analysis module; 
         FIG. 8  illustrates an operation of a content interest processing module; 
         FIG. 9  illustrates a web page portion with mouse move events; 
         FIG. 10  illustrates a table of event data from the mouse move events of  FIG. 9 ; 
         FIG. 11  illustrates a table of attention event data from the mouse move events of  FIG. 9 ; 
         FIG. 12  illustrates a process for selecting an ad using attention data; 
         FIG. 13  illustrates a process for updating ad performance statistics; 
         FIG. 14  illustrates a processor and memory of an ad server; 
         FIG. 15  illustrates an instruction set that may be executed on the processor and memory of  FIG. 14 ; and 
         FIG. 16  illustrates the processor and memory of  FIG. 14  in association with a processor and memory of an event server. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A system in accordance with an embodiment of the disclosure is depicted in  FIG. 1 . In the system  110 , a client  18  provides web page requests  13  to a web server  14 , in response to which, the web server  14  provides page content  11  for display in a browser  15  of the client  18 . Typically, the web page  11  will include visible content  27  as well as Javascript applications. 
     In typical webpage protocols, a document object model (DOM) of a webpage structure may include a document, a body and several elements, including elements embedded within each other. Events, in particular user triggered events such as mouse movements, mouse clicks or keyboard events may be generated at various locations on the page. Application code, e.g. Javascript applications, running in the webpage environment may register event handlers on various web page objects. The event handlers may handle events in a variety of ways. A first event handling method is referred to as event capturing. Event capturing provides an event first to the top most object in the web page hierarchical structure, i.e. DOM, and onward in a descending fashion as follows: 
     DOCUMENT→BODY→ELEMENT A→ELEMENT B 
     Event bubbling provides an event first to the bottom most object and onward in an ascending fashion as follows: 
     ELEMENT B→ELEMENT A→BODY→DOCUMENT 
     The page content  11  may include an ad request URL as a resource. When the client browser  15  loads the web page  11 , an additional request  115  is placed to an ad server processing module  117  of an ad server  112  identified in the ad request URL for dynamic ad content. The ad server  112  accesses an ad data store  128  and provides ad content  116  to be incorporated into the page content. 
     In accordance with an embodiment of the disclosure, the placement of the ad may be performed contextually by reference to a content interest data store  138  of the ad server  112 . The content interest data store stores analyzed attention data. Using the content interest data store, ad content can be selected to match areas of a web page that receive a high amount of user attention. Note that the “areas of a web page” may be restricted as a first step to the web page elements currently in the viewport. The effect of this would be to ignore a most highly attentive web page element (based on aggregate attention data within the data store from many interactions) if that element were no longer in the viewport (in this real time interaction). 
     A method for placing an ad is illustrated in the flowchart  100  of  FIG. 2 . At step  101 , a plurality of candidate advertisements is determined. At step  102 , attention data is retrieved for the content elements of the web page from the content interest data store  138 . The attention data is used to select one of the candidate advertisements  103  and the selected advertisement  116  is provided into the web page at step  104 . In one embodiment, attention data, as will be described in greater detail below, is used to find the DOM element(s) of interest and then a second step is used to select the ad. The second level step may be either performance based or content based. 
     The attention data for the content interest data store  138  may be derived using a system  10  as shown in  FIG. 3  and as described in the Applicant&#39;s co-pending application Attorney Docket No. Hauser 009, the entire contents of which are explicitly incorporated herein by reference. In this system  10 , the web server  14  is modified such that the web page content  11  provided to the client  18  includes an event observer module  26  and layout module  24 , both of which may be provided as appropriate code or scripts that run in the background of the client&#39;s browser  15 . In one embodiment, code for providing the event observer module  26  and the layout module  24  is provided to the web server  14  by a third party service, such as provided from an event server  12 , described in greater detail below. 
     The event observer module  26  and the layout module  24  may be provided as code embedded in a web page  11  from the web server  14 . Alternatively or in addition, the event observer module  26  and the layout module  24  may be provided as a link back to the web server  14  or a third party server, e.g. event server  12 , for the resource containing the code which the web browser will fetch as part of loading the web page. 
     The event observer module  26  observes events generated in a user interaction with the web page  11  at the client  18 . The event observer module  26  records events generated within the web browser  15 , such as mouse clicks, mouse moves, text entries etc., and generates event streams  21  including an event header message  22  and one or more event stream messages  23 . It will be apparent to a person skilled in the art that terms used to describe mouse movements are to be considered broadly and to encompass all such cursor manipulation devices and will include a plug-in mouse, on board mouse, touch pad, pixel pen, etc. 
     The event observer module  26  provides the event streams  21  to the event server  12 . The event server  12  may be as described in the Applicant&#39;s copending application Attorney Docket No. Hauser008, the entire contents of which are explicitly incorporated herein by reference, and includes an event module  25 , an attention analysis module  39 , and a suitable data store  28 , which though shown in  FIG. 3  within the event server  12 , may also be provided as an offsite data store. The event server  12  also includes a service provider module  17  which interfaces with a processing module  19  of the web server  14 . In embodiments of the present disclosure, the event server  12  may also include a content interest analysis module  38 . 
     An example of an event header message  30  is illustrated in  FIG. 4  and an example of an event stream message  40  is illustrated in  FIG. 5 . The messages  30 ,  40  show a number of components that can be included, though in various embodiments, not all of these components may be required and additional components may be added. Primarily, an Interaction_ID  32 ,  42  uniquely identifies an interaction between the client  18  and the web server  14  and aids to identify the particular event stream  21 . The event header message  30  and the event stream message  40  may also identify the Uniform Resource Locator (URL)  31 ,  41 . Fixed parameters such as the operating system  33  and browser type  34  may form part of the event header message  30 . Screen parameters  36 ,  46  such as the screen size, depth and orientation may be included in either or both of the event header message  30  or the event stream message  40 . A capture event stream  43  and a bubble event stream  44  specifies the events recorded in respective event capture and bubbling phases during the web page interaction. Each event may be indicated by the event type, time and x/y location relative to the viewport. Not all web browser types support event capture, and thus the capture event stream  43  may be empty. Where required, events missing from the event bubble stream may be inferred, for example as described in the Applicant&#39;s co-pending application Attorney Docket No. HAUSER002, the entire contents of which are explicitly incorporated herein by reference. An event_count field  45  may indicate the total number of unique events observed by the event observer module including those events not included in the event stream message  40  due to a current event sampling function excluding them. Timing parameters  48  may indicate the relevant period over which the event stream message  40  is current. 
     The event observer module  26  passes the event streams  21  to the event module  25  of the event server  12 . In the embodiment illustrated in  FIG. 3 , the event streams  21  are provided directly to the event module  25 . However, the event streams  21  may also be provided indirectly, e.g. via the web server  14 . 
     The layout module  24  processes the web page content on the client browser  15  and augments the event stream messages  21  with viewport and DOM element layout information. Additional fields of the event stream messages  40  shown in  FIG. 5  include a viewport location  81 , DOM element location changes  82  and DOM structure changes  83 . The DOM element location changes  82  and DOM structure changes  83  may be reported in absolute terms, or may be reported as changes in these parameters since the last report. The viewport location  81  may include a time interval over which the viewport location information can be considered valid. 
     During an interaction with the web page  11 , a user navigates the web page  11  and may enter content where appropriate, such as in the HTML form elements. During this interaction events are generated and recorded by the event observer module  26 . Events may include mouse clicks, mouse moves, key strokes etc. Periodically, the event observer module  26  formulates an event stream message  23 , at which time, the event observer module provides a callback to the layout module  24  for layout data to be included in the event stream message. 
     A process  200  performed by the layout module  24  in response to the callback is shown in  FIG. 6 . The layout module  24  receives the event observer module callback at step  201  and proceeds to compare a current DOM structure of the web page  11  with the last reported DOM structure  202 . The layout module  24  may register itself to watch DOM changes or may simply enumerate the structure as needed. If changes are observed, then a DOM structure summary is provided to the event observer module  26  to be added to the event stream message  23  (step  203 ). At step  204 , the DOM element layout size is compared to the last reported layout size for each DOM element. New elements and any changes of the DOM element layout sizes are communicated  205  to the event observer module  26  for inclusion in the event stream message  23 . The DOM element layout size can be computed using element properties “offset left” and “offset top” as is known. Alternatively, the events generated by the user, e.g. mousemove etc., can be correlated to the first element to see the event in the event bubbling phase. Since the events have x,y coordinate positions, the action of moving the mouse across a DOM element rendered in the viewport window will allow local recording of the size and location of the respective DOM element. At step  206 , the viewport location history is communicated to the event observer module  26  for inclusion in the event stream message  23 , after which the event stream message  23  may be communicated to the event server  12 . 
     The event server  12  receives the event stream  21  including the augmented event stream messages  23  and processes the event streams in the event module  25 . Events may be extracted from the event stream messages  23  together with the viewport data and communicated to the attention analysis module  39  for additional processing. If the event stream  21  includes a new InteractionID, data storage may be allocated in the data store and an initial DOM structure and element layout information may be recorded. When additional event stream messages are received, any updates to the viewport location, DOM structure and DOM element layout are also stored. 
     An operation  300  of the attention analysis module is shown in  FIG. 7 . At step  301 , the attention analysis module  39  receives an analysis trigger, which might be a request, or a timeout. The attention analysis module then analyzes the location of the events in the event stream messages relative to the DOM element location in the viewport in order to compute a probabilistic locus of attention for the user (step  302 ). In one embodiment, the attention analysis module  39  computes the locus of attention from a plurality of mouse move events as these events can provide a fine grained indication of the user&#39;s focus in between mouse clicks. The locus of attention may be computed and stored as the user attention time per DOM element. In addition, the attention analysis module  39  may compute attention events (step  303 ) such as hints, lingers, hovers, partial clicks, cancelled clicks, “on element exits” etc, any of which may assist in determining to where a user&#39;s attention is directed. For example, a mousedown event followed by a mousemove may not register as a complete mouseclick, in particular if the mouseup event occurs off of a particular web page element. However, the mousedown, mousemove and mouseup events together may indicate a region of the user&#39;s interest or attention focus. In a further example, a mouse move followed by a brief period of time before the next mouse move may indicate a hover over a region of interest to the user. 
     The attention time and any attention events may be computed for any DOM element or for DOM elements that have a particular identifier attribute within the page. This allows a web page designer to specify content areas for which to monitor user interest. 
     Once the attention analysis has been performed, an attention data set comprising the results of the attention analysis and the event stream or interaction data may be stored in the data store  28 . A statistical analysis of the attention data set may be performed by the content interest analysis module  38 . By making use of the event data and the attention analysis data in the attention data set, aggregate measures may be formed over multiple URL visits from multiple users to determine a ranking of the content areas of a web page. 
     An example of the statistical analysis is depicted in the flowchart  400  of  FIG. 8 . Content interest analysis may be triggered at step  401  by a periodic timeout, an accumulation of unanalyzed data, a change in DOM structure, receipt of a request, or by any other suitable trigger. Content interest analysis is performed in respect of a URL, so at step  402 , the data store  28  is queried for recent attention analysis data in respect of a particular URL. Any particular web page may be provided with different versions. Different samples of the web page may therefore include differing DOM elements. A query list of all DOM elements for all samples of the URL is constructed at step  403 . A first DOM element is selected at step  404  and a first interaction is selected from the query list at step  405 . If the DOM element is determined to be in the interaction at step  406 , then the amount of time in the DOM element viewport relative to the total viewport time is determined at step  407 . Total viewport time data may be determined from time stamp information  48  in the event stream messages  40  ( FIG. 5 ). Event timing for individual elements within the viewport can be determined from the capture event streams  43  and bubble event streams  44 . 
     The time in viewport may be computed dynamically or may have been computed at an earlier stage, e.g. during attention analysis described above and stored locally. The time in viewport may consider only the active time, that is the time where a certain event rate is maintained rather than the viewport remaining idle. 
     At step  408 , the ratio of attention time and/or attention events attributed to this DOM element relative to the total attention time and/or attention events is computed. Attention events may be those events in the attention analysis data analyzed from the event stream such as hints, lingers, hovers, partial clicks, cancelled clicks and/or “on element” exits. 
     Once the viewport time ratio and the attention event ratios have been calculated for a particular DOM element in a particular interaction, then the process may be repeated for other interactions. If more interactions for the currently selected DOM element exist, as determined at step  409 , then a next interaction is chosen by returning to step  405 . Once all interactions in the query set have been analyzed with respect to the currently selected DOM element, then a next DOM element is selected from the query list, if available (query step  410 ), by returning to step  404  and the interactions for the newly selected DOM element are analyzed following the steps described above. 
     After all DOM elements for the URL have been analyzed, a ranked list of DOM elements can be calculated from the sum of the viewport time ratios and the attention event ratios (step  411 ). The ranked list(s) may be stored locally and/or provided to the content interest data store  138  of an ad server  112  to be stored  412  for later processing as will be described below. 
     While the flowchart  400  of  FIG. 8  depicts one form of statistical analysis, other forms of statistical analysis that process the event stream data to determine the popularity of content areas of the webpage will be apparent to a person skilled in the art. 
     As described in the Applicant&#39;s copending application Attorney Docket No. Hauser008, referenced above, only some of the DOM elements, i.e. particular DOM elements of interest, may undergo attention analysis. In the present disclosure, the content interest analysis module  38  may perform its processing on a subset of DOM elements stored in the data store  28 . When processing is performed on a subset, only the directly correlated data may be used, that is, the data in the event stream and attention analysis stream that is recorded in respect of a DOM element within the subset. Alternatively, the content interest analysis module  38  may process data to DOM elements not in the subset in order to assign the event stream events and attention events to DOM elements in the subset. 
     Within the system, DOM elements may be identified in a number of ways. Typically, DOM elements must be identifiable within the layout module  24 , content interest analysis module  38  and the content interest processing module  19 . DOM element identification is consistent across these components. In one embodiment, the DOM element is identified by a bare identification attribute on the DOM element/page element, by an identifier based on the DOM structure and its location within that structure, or by the element&#39;s pageport location (the pageport is an artificial viewport that is exactly large enough to contain all rendered page elements). 
     In an alternative embodiment, a DOM element identifier may by combined with a hash of the content of the element, a locality sensitive hash (LSH) code of the content of the element, a one-way (cryptographic) hash of the content of the element and/or the actual content of the element. In these embodiments, the content changing within a DOM element can be treated with different interest analysis. If an LSH code is used, such as Nilsimsa digest or similar, it is built using the content of the DOM element (e.g. the text that is displayed) but may optionally be built to include attributes from HTML and/or CSS where those attributes affect the display of the DOM element content. The result is that DOM elements with nearly equivalent content have nearly equivalent LSH codes in their DOM element identifiers. This allows two DOM elements, from different interactions, to be considered the same for analysis if they have sufficiently similar LSH codes. The disadvantage of including more content within the DOM element identifier is that it requires more bandwidth and storage, but has the advantage of allowing greater analysis and security. The DOM element content may be communicated to the event server  12  in the event streams, or, more likely, may be communicated from the web server  14  in response to a content update request from the event server  12 . 
     A magnified sample of an illustrative web page  90  is shown in  FIG. 9 . In the example, the web page  90  includes a body  91 , a div element  92  with “Some Div Text” as its content, a span element  93  with “Some Span Text” as its content and a link element  94  featuring a link as its content. In various embodiments, the link element  94  may be an ad link selected and placed in a manner according to the present disclosure. The representative text is shown in a ghosted font to indicate that the actual content of the web page is relatively unimportant. The important aspects of the page are the page structure, the DOM elements and where the events occur with respect to the DOM elements. 
     In the example, a mouse path  96  registers mouse move events e 1  . . . e 14 . In the events shown, the mouse tracked steadily across the top of the “So” in the rendered &lt;div&gt; text “Some Div Text” (e 1 -e 4 ) and then tracked swiftly down through the word “Some”. The mouse then moved slowly (e 6 -e 9 ) and then tracked upwards to resume a steady pace along the top of the rendered &lt;div&gt; element (e 9 - 14 ). 
     A table representing the mouse move events is shown in  FIG. 10 . For example, the table  110  of  FIG. 10  shows that event e 1  occurred at time=0 and at location x=100, y=100 which, as indicated in the table  110 , occurs in the &lt;div&gt; element  92 . The event type was recorded as a mouse move event. For the path  96  of  FIG. 9 , table  110  of  FIG. 10  indicates that the events e 4 , e 12  were received first in the event bubbling phase by the &lt;body&gt; element event handlers and e 7  was received by the &lt;span&gt; event handlers. That is, in this mouse path  96 , the mouse moved off of the &lt;div&gt; element three times, twice above the rendered &lt;div&gt; text and onto the &lt;body&gt; element (e 4 , e 12 ) and once below the &lt;div&gt; element onto the &lt;span&gt; element (e 7 ). 
       FIG. 11  shows corresponding attention analysis data  120  for the tabulated event  110  data of  FIG. 10 . The attention analysis concludes that events e 1 -e 14  corresponding to time=0 to time=70 constitute a “linger” attention event “a 1 ” and that the attention was focused 100% on the &lt;div&gt; element of the DOM. Also, the downward gesture corresponding to events e 4 -e 10  may be analyzed as a “hint” which has a probabilistic assessment of being a hint of the attention shifting to the &lt;span&gt; element, with a 20% probability, and a hint to the &lt;a id=“link 1 ”&gt; element  94  with a probability of 80%. This example thus shows that a single stream of user events may be analyzed to contain multiple attention events. The attention analysis data  120  may be stored in the data store with the associated event stream provided by table  110 . This example serves to illustrate two additional points. Events may not indicate attention on or for the DOM element on which the events are received e.g. the e 4 , e 7 , and e 12  events are analyzed to indicate the &lt;div&gt; is receiving 100% of the “linger” attention event. Attention may be analyzed to be more relevant to DOM elements that are farther away from the DOM element(s) receiving the events e.g. attention event a 2  receives (derives from) events that arrived on the &lt;div&gt; element but the “hint” was analyzed as being 80% likely relevant to the &lt;a id=“link 1 ”&gt; element which is further away than the &lt;span&gt; element which received only a 20% likelihood of being the target of this “hint” attention event. “Farther away” here means primarily the measure of the DOM elements as rendered in the viewport (viewport rendering location) but could also be approximated using the distance measure of the DOM elements within the structure of the DOM itself (DOM structure location). For the analysis to choose a “farther away” DOM element as the attention event target over a closer DOM element several factors may be considered. The rate of the underlying mouse movement during the events e 4 -e 10  may contribute as may other factors such as the type of a possible target DOM element, if the DOM element is changing (scrolling, animated, video), is the style/color/font different from the source or intervening DOM elements, etc. 
     The attention analysis demonstrated in  FIGS. 9 to 11  describes the analysis performed in respect of a single interaction. By repeating the process across many interactions from many clients for a single URL, aggregate data describing average areas of attention may be statistically determined. 
     The above described embodiments demonstrate a content interest analysis being performed in a distinct event server  12 . In an alternative embodiment, any of the event module  25 , attention analysis module  39  and content interest analysis module  38  may be provided as components of the web server  14 , such that all processing of the event streams, including determining the aggregated areas of interest may be performed within the web server  14 . 
     The event data provides fine grained attention tracking which is hard to falsify by automated means. By performing a statistical analysis of the event data across multiple interactions the most popular areas of a web page that attract the attention may be determined. Such information may be used in many content placement applications. 
     The ad server system  110  of  FIG. 1  may use the attention analysis data to select an ad for placement into a web page. A process for placing an ad is depicted in the flowchart  500  of  FIG. 12 . At step  501 , the ad server processing module  117  of the ad server  112  receives an ad request  115  from which the URL is decoded  502 . At step  503 , the ad data store  128  is queried for candidate ads. Ad candidates may be excluded from selection for a variety of reasons including that the advertiser&#39;s account balance is low, the size of the ad does not fit within the target element, etc. At step  504 , the content interest data store  138  is queried for the attention analysis data in respect of the URL including a ranking of the elements of the page content corresponding to the URL. At step  505 , a decision procedure is used to select an ad from the candidate ads and the ad  116  is provided to the web server  14  or client  15  at step  506 . The decision procedure step  505  uses the attention analysis data to select the most relevant ad for placement into the web page loaded at the client. The relevance of an ad is determined with respect to the content of the more highly ranked elements of the web page. 
     The decision procedure may select an ad by assigning each candidate advertisement with a relevance score. In one embodiment, the relevance score may be calculated by matching the content of the advertisement to the content of the ranked web page elements. The decision procedure may match ads to the most highly ranked element only. For example, a relevance score may be determined for each candidate ad with the relevance score depending only on the content of the ad with respect to the content of the highest ranked element. This embodiment may be considered to have a binary weighting, in which the highest ranked element has a weighting value of 1, and all other elements have a weighting value of zero. 
     In an alternative embodiment, a relevance score may be determined for each candidate ad with the relevance score including a weighting for the degree to which the ad matches the content of the different web page elements. In this embodiment, ads that have low relevance to the top ranked element but high relevance to the page content corresponding to the URL as a whole may still be selected in preference to an ad which has relevance to only the top ranked element of the page content corresponding to the URL. 
     The decision procedure may make use of ad statistics including the performance of an ad. In prior art applications, performance is typically measured by click data. However, using the attention analysis methods described above, ad performance data can be measured even when an ad is not selected by a user. Ad statistics can be updated whenever an attention event indicates an attention shift to an ad element. For the example shown in  FIGS. 9 to 11 , the link  94  may be an ad link and the attention event a 2  is analyzed as an attention hint with the ad link being the destination of the user&#39;s attention shift. Thus, the attention analysis data indicates that the link has been successful in attracting the user&#39;s attention, even though the link was not actually selected. The ad statistics may be updated to record the attention event “a 2 ” shown in  FIG. 11 . When updating the ad statistics for the ad link  94 , the source element is also identified. The source element is the element from which the user attention shifted toward the ad. In the example of  FIGS. 9 to 11 , the source element is the &lt;div&gt; element  92 . The most successful placed ads will be the ads that are relevant to the content chunks that most interest users. The most preferred pattern of behavior is an attention shift from a content chunk of high user interest as the source with the ad as the destination, even if the ad is not always selected. Thus, if an ad repeatedly delivered in a page gets attention but the source element is not within the top ranked content, then the ad may receive a low relevance score. 
     A process for collating ad statistics is illustrated in the flowchart  600  of  FIG. 13 . At step  601 , an ad statistic update is triggered, for example by a timeout, receipt of event stream data to the event server  12 , an ad server request, a user activated trigger, etc. At step  602 , the attention data store  28  is queried for event stream data and attention analysis data in respect of a particular URL and a particular ad. For example, the attention data may indicate time of the ad element in the viewport, a hint, linger, hover, read-over, partial click or select (i.e. click out) in respect of the ad element. If attention data is available for the ad in the URL, then ad statistics may be recorded or updated  603 . In particular, ad statistics may include the source element and the relevance of the ad to the content of the source element. 
     The ad statistics can be used by the decision procedure (step  505 ,  FIG. 12 ) when selecting an ad from the candidate ads. For example, an ad that has a history of attracting user attention from the highest ranked elements of the page content corresponding to the URL may be selected in preference to other candidate ads which may rate more highly on other factors, such as keyword relevance to the page content corresponding to the URL as a whole. 
     In one embodiment, the decision procedure may rely solely on the ad statistics without making use of any content matching. In an alternative embodiment, the decision procedure may combine multiple factors to produce a single relevance score for each candidate advertisement. For example, content matching of the ad to the highest ranked elements may be combined with ad performance statistics for that ad and that web page. Each of these factors may be assigned a weighting when combined into a relevance score. That is, the weighting may favor ads that have historically produced attention events when placed within the particular web page so that these ads will generate a higher relevance score during the decision procedure. 
     Once the relevance scores have been determined for the candidate ads, the most relevant ad may be selected and placed within the web page. 
     While the above described embodiments make specific reference to ranking the DOM elements of page content corresponding to a URL for their user content interest, the ranking may be performed in respect of other elements and divisions of a web page. 
     An advantage of the presently described embodiments for contextual placement of dynamic content includes that the contextual placement is determined not on the page content corresponding to the URL as a whole, but on those portions of the page content corresponding to the URL that are most popular. For example, a keyword may appear multiple times in a lowly ranked element of a document and would therefore be highly ranked for ad placements on prior art contextual placement arrangements. However, an ad that matches this keyword may be unlikely to be selected by the user because the user&#39;s attention is not directed to the lowly ranked elements in which the keyword appears. Keywords appearing fewer times in the whole page content corresponding to the URL but appearing in the more highly ranked elements are more likely to be selected and thus by placing ads dependent on the content interest areas of a web page, greater ad effectiveness can be achieved. 
     While the illustrated embodiments depict the ad server  112  and the event server  12  as separate entities, they may be incorporated into a single entity with the content interest data store  138  of the ad server  112  being incorporated within the data store  28  of the event server. In an alternative embodiment, the content interest data store  138  may be incorporated within the data store  28  of the event server  12  with the ad server processing module  117  accessing the data store  28  when attention data is required. 
     The ad server  112  may be embodied in hardware, software, firmware or a combination of hardware, software and/or firmware. In a hardware embodiment, the ad server  112  may be provided in a device, such as server hardware, computer, etc including a processor  61  operatively associated with a memory  62  as shown in  FIG. 14 . The memory  62  may store instructions that are executable on the processor  61 . In addition, the memory  62  may provide elements of the ad data store  128  and/or attention data store  138 . An instruction set  700  that may be executed on the event server processor  61  is depicted in the flowchart of  FIG. 15 . Specifically, when executed, the instruction set  700  allows the processor to receive an advertisement placement request in respect of a URL at step  701 . At step  702 , a document object model of a web page corresponding to the URL is determined and a plurality of document object model elements of the URL are determined at step  703 . At step  704 , the processor retrieves an attention ranking of the document object model elements. The processor determines candidate advertisements at step  705  and determines a relevance score for each candidate advertisement  706  before selecting an advertisement from the plurality of candidate advertisements dependent on the relevance scores  707 . The relevance score may be determined by calculating a content matching factor dependent on a match of the content of the advertisement to the content of a document object model element. The content matching factor may then be weighted based on the rank of the respective document object model element. 
     The document object model structure including the document object model elements may be retrieved by looking up information for the URL stored in memory  62  or by retrieving the information from associated or offsite resources such as the event server  12 . The ad server processor  61  may communicate with a processor  71  of the event server, as shown in  FIG. 16 , through a suitable communications link  65 . The DOM structure and content interest data including the ranked DOM element list may be stored in the memory  72  of the event server and communicated to the ad server processor  61  through the link  65 . 
     The person skilled in the art will readily understand that the sequence of steps shown in the Figures and is provided for illustrative purposes only and that the order of steps is not essential. Furthermore, the person skilled in the art will recognize that a greater or lesser number of steps may be performed without departing from the scope of the disclosure. 
     Although embodiments of the present invention have been illustrated in the accompanied drawings and described in the foregoing description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit of the invention as set forth and defined by the following claims. For example, the capabilities of the invention can be performed fully and/or partially by one or more of the blocks, modules, processors or memories. Also, these capabilities may be performed in the current manner or in a distributed manner and on, or via, any device able to provide and/or receive information. Further, although depicted in a particular manner, various modules or blocks may be repositioned without departing from the scope of the current invention. Still further, although depicted in a particular manner, a greater or lesser number of modules and connections can be utilized with the present invention in order to accomplish the present invention, to provide additional known features to the present invention, and/or to make the present invention more efficient. Also, the information sent between various modules can be sent between the modules via at least one of a data network, the Internet, an Internet Protocol network, a wireless source, and a wired source and via plurality of protocols.