Patent Publication Number: US-10789258-B2

Title: Systems and methods for content presentation

Description:
FIELD OF THE INVENTION 
     The present technology relates to the field of content presentation. More particularly, the present technology relates to techniques for presenting content items through computing devices. 
     BACKGROUND 
     Today, people often utilize computing devices (or systems) for a wide variety of purposes. Users can operate their computing devices to, for example, interact with one another, create content, share content, and access information. Under conventional approaches, content items (e.g., images, videos, audio files, etc.) can be made available through a content provider platform (e.g., a social networking system). Users can operate their computing devices to access the content items through the platform. Typically, the content items can be provided, or uploaded, by various entities including, for example, content publishers and also users of the content provider platform. 
     SUMMARY 
     Various embodiments of the present disclosure can include systems, methods, and non-transitory computer readable media configured to obtain at least one content item to be scored with respect to a user, wherein the score is used to determine whether the content item is included in a content feed of the user. A value for a first event is determined based at least in part on a likelihood of the user performing an action with respect to the content item, wherein the likelihood of the user performing the action is greater than an average user of the social networking system. The score for the content item is determined based at least in part on the value for the first event, wherein the first value is dampened to reduce its contribution to the score. 
     In an embodiment, the systems, methods, and non-transitory computer readable media are configured to determine a product of the likelihood of the user performing the first action with respect to the content item and a corresponding weight for the first action. 
     In an embodiment, the action involves the user performing one of: a like action with respect to the content item, a hide action with respect to the content item, a share action with respect to the content item, a comment action with respect to the content item, or viewing the content item. 
     In an embodiment, the systems, methods, and non-transitory computer readable media are configured to determine a value for a second event based at least in part on a likelihood of the user performing a second action with respect to the content item and to determine the score for the content item based at least in part on a sum of the value and the second value. 
     In an embodiment, the systems, methods, and non-transitory computer readable media are configured to determine a product of the value and a term to dampen the value, the term being based at least in part on a number of times the user performed the negative action over a period of time. 
     In an embodiment, the term is a fraction having a numerator of 1 and a denominator of h, wherein h represents a number of times the user performed the negative action over a period of time. 
     In an embodiment, the negative action corresponds to a hide action, and wherein h represents a number of times the user hid content items over a period of time. 
     In an embodiment, the systems, methods, and non-transitory computer readable media are configured to determine a product of the value and a term to dampen the value, the term being based at least in part on a set of probabilities that each correspond to the user performing the positive action at some percentile. 
     In an embodiment, the term is a fraction having a numerator corresponding to a probability of the user performing the action at a first percentile and a denominator corresponding to a sum of probabilities of the user performing the action at at least a second percentile and a third percentile. 
     In an embodiment, the content item is an image, video, audio file, page, user profile, group, story, or post. 
     It should be appreciated that many other features, applications, embodiments, and/or variations of the disclosed technology will be apparent from the accompanying drawings and from the following detailed description. Additional and/or alternative implementations of the structures, systems, non-transitory computer readable media, and methods described herein can be employed without departing from the principles of the disclosed technology. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example system including an example content provider module configured to provide content to users, according to an embodiment of the present disclosure. 
         FIG. 2  illustrates an example of a content module configured to provide content items through content feeds, according to an embodiment of the present disclosure. 
         FIG. 3  illustrates an example of a scoring module configured to score content items, according to an embodiment of the present disclosure. 
         FIG. 4  illustrates an example method for scoring content items, according to an embodiment of the present disclosure. 
         FIG. 5  illustrates an example method for scoring content items, according to an embodiment of the present disclosure. 
         FIG. 6  illustrates a network diagram of an example system including an example social networking system that can be utilized in various scenarios, according to an embodiment of the present disclosure. 
         FIG. 7  illustrates an example of a computer system or computing device that can be utilized in various scenarios, according to an embodiment of the present disclosure. 
     
    
    
     The figures depict various embodiments of the disclosed technology for purposes of illustration only, wherein the figures use like reference numerals to identify like elements. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated in the figures can be employed without departing from the principles of the disclosed technology described herein. 
     DETAILED DESCRIPTION 
     Approaches for Content Presentation 
     People use computing devices (or systems) for a wide variety of purposes. As mentioned, under conventional approaches, a user can utilize a computing device to share content items (e.g., documents, images, videos, audio, etc.) with other users. Under conventional approaches, content items (e.g., images, videos, audio files, etc.) can be made available through a content sharing platform. Users can operate their computing devices to access the content items through the platform. Typically, the content items can be provided, or uploaded, by various entities including, for example, content publishers and also users of the content sharing platform. 
     In some instances, a user operating a computing device can interact with a content provider interface (e.g., a software application running on the computing device, web browser, etc.) to access content items. Such content items, or snippets (e.g., title, summary, text excerpt, images, frames, etc.) of content items, can be presented through the interface as part of a content feed, for example. Users can navigate (e.g., browse) the content feed, for example, by scrolling or performing some gesture through a display screen of the computing device, to access the different content items that are available in the content feed. At any given time, there may be a large number of content items that are presented in a user&#39;s content feed. 
     In general, a respective score is generated for each content item that is eligible to be presented in the user&#39;s content feed. In various embodiments, a content item can be an image, video, audio file, page, user profile, group, story, place (e.g., point of interest, city, etc.), or post, to name some examples. A content item&#39;s score can be used to determine whether the content item is presented in the user&#39;s content feed, for example, based on the content item&#39;s score satisfying a threshold score, and also the rank in which the content item is presented in the content feed. Typically, each content item is scored with respect to a user. In other words, the same content item can have a different score depending on the user. The score for each content item can be determined, for example, based on a sum of values that correspond to various events. The value for each event can be determined based, in part, on a likelihood of the user performing some action (e.g., like, hide, comment, share, etc.). For example, one event can correspond to a likelihood of the user “liking” a content item (e.g., by selecting a “like” option associated with the content item). In this example, the value for this event can be determined as follows: P like *W like , where P like  represents a probability that the user will like the content item and W like  represents a weight associated with the “like” action. In various embodiments, the respective probabilities for each user performing various actions (e.g., like, hide, share, comment, watch a video, etc.) are obtained from a trained machine learning model. 
     In some instances, scoring content items using the approach described above can result in a sub-optimal experience for some users when those users excessively perform certain action(s) more so than an average user. For example, a user may tend to select the like option, for example, for an above-average number of content items that appear in the user&#39;s content feed. As a result, the user&#39;s P like  value (i.e., the likelihood of the user liking a content item) may become much larger than that of an average user. This behavior can result in the scores determined for content items based, in part, on the user&#39;s P like  value to become anomalous when compared to that of an average user. Such anomalies can result in a sub-optimal experience for the user which may involve, for example, the exclusion of content items that would normally be included in the user&#39;s content feed and/or reducing the respective contributions to the score by other events (e.g., a likelihood of the user sharing the content item). Accordingly, such conventional approaches can be inconvenient to users and may not be effective in addressing these and other problems arising in computer technology. 
     An improved approach rooted in computer technology overcomes the foregoing and other disadvantages associated with conventional approaches specifically arising in the realm of computer technology. In various embodiments, content items can be scored to prevent anomalies that may arise due to abnormal user behavior, as described above. In some embodiments, the values of one or more events that are used to determine a content item score can be adjusted (e.g., increased or decreased) by some factor, or amount, so that content items can be scored optimally. As a result, users that exhibit abnormal behavior, which may involve performing some action more frequently or less frequently than an average user, can still have an optimal browsing experience with respect to their content feed. 
       FIG. 1  illustrates an example system  100  including an example content provider module  102  configured to provide content to users, according to an embodiment of the present disclosure. As shown in the example of  FIG. 1 , the content provider module  102  can include an interface module  104  and a content module  106 . In some instances, the example system  100  can include at least one data store  108 . The components (e.g., modules, elements, etc.) shown in this figure and all figures herein are exemplary only, and other implementations may include additional, fewer, integrated, or different components. Some components may not be shown so as not to obscure relevant details. 
     In some embodiments, the content provider module  102  can be implemented, in part or in whole, as software, hardware, or any combination thereof. In general, a module, as discussed herein, can be associated with software, hardware, or any combination thereof. In some implementations, one or more functions, tasks, and/or operations of modules can be carried out or performed by software routines, software processes, hardware, and/or any combination thereof. In some cases, the content provider module  102  can be implemented, in part or in whole, as software running on one or more computing devices or systems, such as on a user computing device or client computing system. For example, the content provider module  102 , or at least a portion thereof, can be implemented as or within an application (e.g., app), a program, or an applet, etc., running on a user computing device or a client computing system, such as the user device  610  of  FIG. 6 . Further, the content provider module  102 , or at least a portion thereof, can be implemented using one or more computing devices or systems that include one or more servers, such as network servers or cloud servers. In some instances, the content provider module  102  can, in part or in whole, be implemented within or configured to operate in conjunction with a social networking system (or service), such as the social networking system  630  of  FIG. 6 . It should be understood that there can be many variations or other possibilities. 
     In some embodiments, the content provider module  102  can be configured to communicate and/or operate with the at least one data store  108  in the example system  100 . The at least one data store  108  can be configured to store and maintain various types of data. In various embodiments, the at least one data store  108  can store data relevant to function and operation of the content provider module  102  including, for example, content items that are available for access through the social networking system as well as data for various users describing their respective likelihoods of performing various actions with respect to content items. In some implementations, the at least one data store  108  can store information associated with the social networking system (e.g., the social networking system  630  of  FIG. 6 ). The information associated with the social networking system can include data about users, social connections, social interactions, locations, geo-fenced areas, maps, places, events, pages, groups, posts, communications, content, feeds, account settings, privacy settings, a social graph, and various other types of data. In some implementations, the at least one data store  108  can store information associated with users, such as user identifiers, user information, profile information, user specified settings, content produced or posted by users, and various other types of user data. It should be appreciated that there can be many variations or other possibilities. 
     In various embodiments, the content provider module  102  can utilize the interface module  104  and the content module  106  to provide content items to users. The interface module  104  can be configured to provide an interface (e.g., graphical user interface) through which content items can be presented and accessed. For example, the interface can be provided through a software application (e.g., social networking application) running on a computing device being operated by a user. The user can interact with the interface, for example, by performing touch screen gestures through a display screen of the computing device. As mentioned, in some embodiments, content items can be presented through the interface as part of a content feed, which the user can navigate to access or browse content items. As mentioned, each content item can be scored and ranked in the content feed based on its respective score. 
     The content module  106  can be configured to provide various types of content items that can be presented to users through the interface provided by the interface module  104 . More details regarding the content module  106  will be provided below in reference to  FIG. 2 . 
       FIG. 2  illustrates an example of a content module  202  configured to provide content items, according to an embodiment of the present disclosure. In some embodiments, the content module  106  of  FIG. 1  can be implemented with the content module  202 . As shown in the example of  FIG. 2 , the content module  202  can include a content feed module  204  and a scoring module  206 . 
     In various embodiments, the content feed module  204  provides the content items through a respective content feed (e.g., news feed) that is customized for each user of the social networking system. The content feed can include content items (or stories) that have been selected for presentation to the user. Such content items may be selected from various content items that may be provided (e.g., uploaded or shared) by other users of the social networking system or by various third-party content publishers, for example. 
     In various embodiments, the scoring module  206  is configured to score each content item that is eligible for inclusion in a user&#39;s content feed. Such scores are then used to determine whether a content item should be included in the user&#39;s content feed, for example, based on the content item&#39;s score satisfying a threshold score as well as the order in which the content item is presented in the content feed. More details regarding the scoring module  206  will be provided below in reference to  FIG. 3 . 
       FIG. 3  illustrates an example of a scoring module  302  configured to score content items, according to an embodiment of the present disclosure. In some embodiments, the scoring module  206  of  FIG. 2  can be implemented with the scoring module  302 . As shown in the example of  FIG. 3 , the scoring module  302  can include a content item scoring module  304  and an event module  306 . 
     The content item scoring module  304  is configured to determine a respective score for each content item. In general, the score generated for a content item is specific to a user. In other words, the same content item can have a different score depending on the user. In various embodiments, the score generated for each content item is determined based on one or more events. In general, each event corresponds to some action and the value determined for the event is based on a likelihood of a user performing that action. One example event corresponds to a “like” action and this event can measure a likelihood of a particular user liking a content item (e.g., by selecting a “like” option associated with the content item) as follows:
 
 E   like   =P   like   *W   like ,
 
     where E like  represents the value determined for the “like” event, where P like  represents a user specific probability that the user will like the content item, and where W like  represents a weight associated with the like action. As shown, the P like  value can be adjusted by a corresponding weight value W like . Each event can be assigned its own respective weight value which may be some numerical value. This weight can be used to increase or decrease the effect an event has on the overall score for a content item. 
     In various embodiments, the score generated for each content item is based on a sum of values that correspond to various events. One example approach for calculating the score of a content item with respect to a user is as follows:
 
Score content item   =E   1   + . . . +E   n  
 
     where E 1  represents a value determined for a first event with respect to the user and where E n  represents a value determined for an event n with respect to the user. 
     As shown, the score for a content item can be determined based on other events in addition to the like action. Another example event includes a hide action, which measures a likelihood of a user hiding a content item (e.g., by selecting a “hide” option associated with the content item). Similarly, there can be additional events that each correspond to one of: a likelihood of the user sharing the content item (e.g., by selecting a “share” option associated with the content item), a likelihood of the user commenting on the content item (e.g., by submitting a comment to be posted with the content item), a likelihood of the user watching the content item (e.g., watching a video), to name some examples. 
     In some embodiments, the weight assigned to an event can vary depending on whether the event is considered a positive action or a negative action. In general, an event that is considered a positive action causes the score for a content item to increase, such as a like action, a comment action, a share option, reading or watching a content item, etc. For these events, their corresponding weight is typically a positive value so that the values determined of these events (e.g., P n *W n ) causes the overall score for the content item to increase. In such embodiments, a content item having a higher score increases the chances of the score satisfying a threshold score, which typically results in the content item being included in the user&#39;s content feed. Weights may be assigned in a manner that reflects the relative importance of one event over another. For example, a like action may be weighted using a first value, e.g., 5, whereas a comment action can be weighted higher, e.g., 50, to amplify its contribution to the overall score for the content item. In contrast, some events may be associated with a negative action, such as the hide action. For these events, their corresponding weight is typically a negative value so that the values determined of these events (e.g., P n *W n ) causes the overall score for the content item to decrease. For example, a hide action may be associated with a negative weight, e.g., −100, so that the value determined for this event (e.g., P hide *(−100)), causes the overall score for the content item to decrease. 
     As mentioned, in some instances, users can perform actions that cause the values determined for one or more events to become anomalous, thereby affecting the overall content item scores that are determined for such users. For example, a user may tend to select the like option for an above-average number of content items that appear in the user&#39;s content feed. As a result, the user&#39;s P like  value (i.e., the likelihood of the user liking a content item) may become much larger than that of an average user. This behavior can result in the scores determined for content items based, in part, on the user&#39;s P like  value to become anomalous when compared to that of an average user. Such anomalies can result in a sub-optimal experience for the user which may involve, for example, the exclusion of content items that would normally be included in the user&#39;s content feed. 
     In various embodiments, the event module  306  can be configured to apply event-specific approaches to prevent anomalous content item scores from being generated. As mentioned, the score generated for each content item can be based on a sum of values that each correspond to an event. Each event typically corresponds to some action and the value determined for the event is based on a likelihood of a user performing that action. Thus, any one event can cause the score determined for a content item to become anomalous. 
     In various embodiments, the approach applied to an event depends on the event type. In one example, a user that selects the hide option for an above-average number of content items can cause the user&#39;s P hide  value (i.e., the likelihood of the user selecting a hide option associated with a content item) to become much larger than that of an average user. As mentioned, this behavior can result in the scores determined for content items based, in part, on the user&#39;s P hide  value to become anomalous when compared to that of an average user. In some embodiments, the event module  306  adjusts the value determined for the event corresponding to the hide option based on the number of times the user selected the hide option over some period of time (e.g., one week, month, year, etc.). For example, in some embodiments, the value determined for the event corresponding to the hide option can be adjusted by a term T as follows:
 
 E   hide   =P   hide   *T*W   hide ,
 
     where E hide  represents the value determined for the “hide” event, where P hide  represents a user specific probability that the user will hide the content item, where W hide  represents a weight associated with the hide action, where T is a fraction having a numerator of 1 and a denominator of h (i.e., T=1/h), and where h represents the number of times the user selected the hide option for content items over some period of time. Using this approach, the value determined for the hide event, E hide , is damped by the number of times the user selected the hide option. In other words, the E hide  value for a user that excessively selects the hide option is normalized by the term T despite the likelihood of that user hiding content items, P hide , being abnormally high. Users that do not frequently hide content items are less affected by the term T. This approach described above may be used for other negative action events as well. 
     The event module  306  can be configured to apply separate approaches to other types of events. As mentioned, other example events can include a like event (e.g., based on a likelihood of a user liking a content item), a share event (e.g., based on a likelihood of a user sharing a content item), a comment event (e.g., based on a likelihood of a user commenting on a content item), a watch event (e.g., based on a likelihood of a user watching a content item, such as a video). In some instances, a user with a high likelihood of performing some action (e.g., like, share, comment, etc.) causes the value for the event corresponding to that action to become high. This can result in the respective contributions of other events included in the content item score calculation (e.g., the share event, comment event, etc.) to diminish. For example, a user with a high likelihood of “liking” content items causes the user&#39;s like event (e.g., E like =P like *W like ) to become high. As a result, other events included in the content item score calculation have a reduced impact on the overall score calculated for a content item. To prevent this result, in some embodiments, the event module  306  adjusts the value determined for an event based on a set of percentiles (e.g., p25, p50, p75, p90, etc.) that correspond to a respective probability of a user performing an action corresponding to the event. Using the like event as an example, the event module  306  can determine the respective probabilities of a user liking a content item at the 25 th  percentile (i.e., p25), the 50 th  percentile (i.e., p50), the 75 th  percentile (i.e., p75), and the 90 th  percentile (i.e., p90). Such percentiles can be determined from a probability distribution, as illustrated in  FIG. 4 . The set of percentiles (e.g., p25, p50, p75, p90, etc.) that correspond to a respective probability of a user liking a content item can be determined based on this probability distribution. In one example, the p25 probability for a user may be 0.12, the p50 probability for the user may be 0.18, the p75 probability for the user may be 0.27, and the p90 probability for the user may be 0.37. In some embodiments, the value determined for the event corresponding to the like option can be adjusted by a set of percentiles as follows:
 
 E   like   =P   like   *T*W   like ,
 
     where E like  represents the value determined for the “like” event, where P like  represents a user specific probability that the user will like the content item, where W like  represents a weight associated with the like action, and where T is a fraction having a numerator corresponding to the first percentile probability (e.g., the probability of the user liking a content item at the x th  percentile) and a denominator corresponding to at least a second percentile probability (e.g., the probability of the user liking a content item at the y th  percentile). For example, in some embodiments T is a fraction having a numerator of p90 and a denominator of a sum of p25, p50, and p75, e.g., 
             T   =         p   ⁢           ⁢   90       (       p   ⁢           ⁢   25     +     p   ⁢           ⁢   50     +     p   ⁢           ⁢   75       )       .           
The set of percentiles used for can vary depending on the implementation. For example, in some embodiments,
 
     
       
         
           
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     Using this approach, the value determined for the like event, E like , is devalued for users that tend to excessively like content items. In other words, the E like  value for a user that excessively selects the like option is normalized by the term T despite the likelihood of that user liking content items, P like , being abnormally high. In some embodiments, the respective values determined for other events (e.g., positive action events such as the comment event and the share event) are also adjusted by a set of percentiles as described above. 
       FIG. 4  illustrates an example probability distribution  402  for a user liking a content item. In various embodiments, the probability distribution  402  can be generated separately for each user of the social networking system. In the example probability distribution  402 , the y-axis corresponds to the number of content items and the x-axis corresponds to the probability of the user liking a content item. A set of percentiles (e.g., p25, p50, p75, p90, etc.)  404  can be determined using the probability distribution  402 . Such percentiles can be used to adjust values for various events (e.g., events corresponding to positive actions), for example. 
       FIG. 5  illustrates an example method  500  for scoring content items, according to an embodiment of the present disclosure. It should be appreciated that there can be additional, fewer, or alternative steps performed in similar or alternative orders, or in parallel, within the scope of the various embodiments discussed herein unless otherwise stated. At block  502 , at least one content item to be scored with respect to a user is obtained, wherein the score is used to determine whether the content item is included in a content feed of the user. At block  504 , a value for a first event is determined based at least in part on a likelihood of the user performing an action with respect to the content item, wherein the likelihood of the user performing the action is greater than an average user of the social networking system. At block  506 , the score for the content item is determined based at least in part on the value for the first event, wherein the first value is dampened to reduce its contribution to the score. 
     It is contemplated that there can be many other uses, applications, and/or variations associated with the various embodiments of the present disclosure. For example, in some cases, user can choose whether or not to opt-in to utilize the disclosed technology. The disclosed technology can also ensure that various privacy settings and preferences are maintained and can prevent private information from being divulged. In another example, various embodiments of the present disclosure can learn, improve, and/or be refined over time. 
     Social Networking System—Example Implementation 
       FIG. 6  illustrates a network diagram of an example system  600  that can be utilized in various scenarios, in accordance with an embodiment of the present disclosure. The system  600  includes one or more user devices  610 , one or more external systems  620 , a social networking system (or service)  630 , and a network  650 . In an embodiment, the social networking service, provider, and/or system discussed in connection with the embodiments described above may be implemented as the social networking system  630 . For purposes of illustration, the embodiment of the system  600 , shown by  FIG. 6 , includes a single external system  620  and a single user device  610 . However, in other embodiments, the system  600  may include more user devices  610  and/or more external systems  620 . In certain embodiments, the social networking system  630  is operated by a social network provider, whereas the external systems  620  are separate from the social networking system  630  in that they may be operated by different entities. In various embodiments, however, the social networking system  630  and the external systems  620  operate in conjunction to provide social networking services to users (or members) of the social networking system  630 . In this sense, the social networking system  630  provides a platform or backbone, which other systems, such as external systems  620 , may use to provide social networking services and functionalities to users across the Internet. 
     The user device  610  comprises one or more computing devices (or systems) that can receive input from a user and transmit and receive data via the network  650 . In one embodiment, the user device  610  is a conventional computer system executing, for example, a Microsoft Windows compatible operating system (OS), Apple OS X, and/or a Linux distribution. In another embodiment, the user device  610  can be a computing device or a device having computer functionality, such as a smart-phone, a tablet, a personal digital assistant (PDA), a mobile telephone, a laptop computer, a wearable device (e.g., a pair of glasses, a watch, a bracelet, etc.), a camera, an appliance, etc. The user device  610  is configured to communicate via the network  650 . The user device  610  can execute an application, for example, a browser application that allows a user of the user device  610  to interact with the social networking system  630 . In another embodiment, the user device  610  interacts with the social networking system  630  through an application programming interface (API) provided by the native operating system of the user device  610 , such as iOS and ANDROID. The user device  610  is configured to communicate with the external system  620  and the social networking system  630  via the network  650 , which may comprise any combination of local area and/or wide area networks, using wired and/or wireless communication systems. 
     In one embodiment, the network  650  uses standard communications technologies and protocols. Thus, the network  650  can include links using technologies such as Ethernet, 802.11, worldwide interoperability for microwave access (WiMAX), 3G, 4G, CDMA, GSM, LTE, digital subscriber line (DSL), etc. Similarly, the networking protocols used on the network  650  can include multiprotocol label switching (MPLS), transmission control protocol/Internet protocol (TCP/IP), User Datagram Protocol (UDP), hypertext transport protocol (HTTP), simple mail transfer protocol (SMTP), file transfer protocol (FTP), and the like. The data exchanged over the network  650  can be represented using technologies and/or formats including hypertext markup language (HTML) and extensible markup language (XML). In addition, all or some links can be encrypted using conventional encryption technologies such as secure sockets layer (SSL), transport layer security (TLS), and Internet Protocol security (IPsec). 
     In one embodiment, the user device  610  may display content from the external system  620  and/or from the social networking system  630  by processing a markup language document  614  received from the external system  620  and from the social networking system  630  using a browser application  612 . The markup language document  614  identifies content and one or more instructions describing formatting or presentation of the content. By executing the instructions included in the markup language document  614 , the browser application  612  displays the identified content using the format or presentation described by the markup language document  614 . For example, the markup language document  614  includes instructions for generating and displaying a web page having multiple frames that include text and/or image data retrieved from the external system  620  and the social networking system  630 . In various embodiments, the markup language document  614  comprises a data file including extensible markup language (XML) data, extensible hypertext markup language (XHTML) data, or other markup language data. Additionally, the markup language document  614  may include JavaScript Object Notation (JSON) data, JSON with padding (JSONP), and JavaScript data to facilitate data-interchange between the external system  620  and the user device  610 . The browser application  612  on the user device  610  may use a JavaScript compiler to decode the markup language document  614 . 
     The markup language document  614  may also include, or link to, applications or application frameworks such as FLASH™ or Unity™ applications, the Silverlight™ application framework, etc. 
     In one embodiment, the user device  610  also includes one or more cookies  616  including data indicating whether a user of the user device  610  is logged into the social networking system  630 , which may enable modification of the data communicated from the social networking system  630  to the user device  610 . 
     The external system  620  includes one or more web servers that include one or more web pages  622   a ,  622   b , which are communicated to the user device  610  using the network  650 . The external system  620  is separate from the social networking system  630 . For example, the external system  620  is associated with a first domain, while the social networking system  630  is associated with a separate social networking domain. Web pages  622   a ,  622   b , included in the external system  620 , comprise markup language documents  614  identifying content and including instructions specifying formatting or presentation of the identified content. As discussed previously, it should be appreciated that there can be many variations or other possibilities. 
     The social networking system  630  includes one or more computing devices for a social network, including a plurality of users, and providing users of the social network with the ability to communicate and interact with other users of the social network. In some instances, the social network can be represented by a graph, i.e., a data structure including edges and nodes. Other data structures can also be used to represent the social network, including but not limited to databases, objects, classes, meta elements, files, or any other data structure. The social networking system  630  may be administered, managed, or controlled by an operator. The operator of the social networking system  630  may be a human being, an automated application, or a series of applications for managing content, regulating policies, and collecting usage metrics within the social networking system  630 . Any type of operator may be used. 
     Users may join the social networking system  630  and then add connections to any number of other users of the social networking system  630  to whom they desire to be connected. As used herein, the term “friend” refers to any other user of the social networking system  630  to whom a user has formed a connection, association, or relationship via the social networking system  630 . For example, in an embodiment, if users in the social networking system  630  are represented as nodes in the social graph, the term “friend” can refer to an edge formed between and directly connecting two user nodes. 
     Connections may be added explicitly by a user or may be automatically created by the social networking system  630  based on common characteristics of the users (e.g., users who are alumni of the same educational institution). For example, a first user specifically selects a particular other user to be a friend. Connections in the social networking system  630  are usually in both directions, but need not be, so the terms “user” and “friend” depend on the frame of reference. Connections between users of the social networking system  630  are usually bilateral (“two-way”), or “mutual,” but connections may also be unilateral, or “one-way.” For example, if Bob and Joe are both users of the social networking system  630  and connected to each other, Bob and Joe are each other&#39;s connections. If, on the other hand, Bob wishes to connect to Joe to view data communicated to the social networking system  630  by Joe, but Joe does not wish to form a mutual connection, a unilateral connection may be established. The connection between users may be a direct connection; however, some embodiments of the social networking system  630  allow the connection to be indirect via one or more levels of connections or degrees of separation. 
     In addition to establishing and maintaining connections between users and allowing interactions between users, the social networking system  630  provides users with the ability to take actions on various types of items supported by the social networking system  630 . These items may include groups or networks (i.e., social networks of people, entities, and concepts) to which users of the social networking system  630  may belong, events or calendar entries in which a user might be interested, computer-based applications that a user may use via the social networking system  630 , transactions that allow users to buy or sell items via services provided by or through the social networking system  630 , and interactions with advertisements that a user may perform on or off the social networking system  630 . These are just a few examples of the items upon which a user may act on the social networking system  630 , and many others are possible. A user may interact with anything that is capable of being represented in the social networking system  630  or in the external system  620 , separate from the social networking system  630 , or coupled to the social networking system  630  via the network  650 . 
     The social networking system  630  is also capable of linking a variety of entities. For example, the social networking system  630  enables users to interact with each other as well as external systems  620  or other entities through an API, a web service, or other communication channels. The social networking system  630  generates and maintains the “social graph” comprising a plurality of nodes interconnected by a plurality of edges. Each node in the social graph may represent an entity that can act on another node and/or that can be acted on by another node. The social graph may include various types of nodes. Examples of types of nodes include users, non-person entities, content items, web pages, groups, activities, messages, concepts, and any other things that can be represented by an object in the social networking system  630 . An edge between two nodes in the social graph may represent a particular kind of connection, or association, between the two nodes, which may result from node relationships or from an action that was performed by one of the nodes on the other node. In some cases, the edges between nodes can be weighted. The weight of an edge can represent an attribute associated with the edge, such as a strength of the connection or association between nodes. Different types of edges can be provided with different weights. For example, an edge created when one user “likes” another user may be given one weight, while an edge created when a user befriends another user may be given a different weight. 
     As an example, when a first user identifies a second user as a friend, an edge in the social graph is generated connecting a node representing the first user and a second node representing the second user. As various nodes relate or interact with each other, the social networking system  630  modifies edges connecting the various nodes to reflect the relationships and interactions. 
     The social networking system  630  also includes user-generated content, which enhances a user&#39;s interactions with the social networking system  630 . User-generated content may include anything a user can add, upload, send, or “post” to the social networking system  630 . For example, a user communicates posts to the social networking system  630  from a user device  610 . Posts may include data such as status updates or other textual data, location information, images such as photos, videos, links, music or other similar data and/or media. Content may also be added to the social networking system  630  by a third party. Content “items” are represented as objects in the social networking system  630 . In this way, users of the social networking system  630  are encouraged to communicate with each other by posting text and content items of various types of media through various communication channels. Such communication increases the interaction of users with each other and increases the frequency with which users interact with the social networking system  630 . 
     The social networking system  630  includes a web server  632 , an API request server  634 , a user profile store  636 , a connection store  638 , an action logger  640 , an activity log  642 , and an authorization server  644 . In an embodiment of the invention, the social networking system  630  may include additional, fewer, or different components for various applications. Other components, such as network interfaces, security mechanisms, load balancers, failover servers, management and network operations consoles, and the like are not shown so as to not obscure the details of the system. 
     The user profile store  636  maintains information about user accounts, including biographic, demographic, and other types of descriptive information, such as work experience, educational history, hobbies or preferences, location, and the like that has been declared by users or inferred by the social networking system  630 . This information is stored in the user profile store  636  such that each user is uniquely identified. The social networking system  630  also stores data describing one or more connections between different users in the connection store  638 . The connection information may indicate users who have similar or common work experience, group memberships, hobbies, or educational history. Additionally, the social networking system  630  includes user-defined connections between different users, allowing users to specify their relationships with other users. For example, user-defined connections allow users to generate relationships with other users that parallel the users&#39; real-life relationships, such as friends, co-workers, partners, and so forth. Users may select from predefined types of connections, or define their own connection types as needed. Connections with other nodes in the social networking system  630 , such as non-person entities, buckets, cluster centers, images, interests, pages, external systems, concepts, and the like are also stored in the connection store  638 . 
     The social networking system  630  maintains data about objects with which a user may interact. To maintain this data, the user profile store  636  and the connection store  638  store instances of the corresponding type of objects maintained by the social networking system  630 . Each object type has information fields that are suitable for storing information appropriate to the type of object. For example, the user profile store  636  contains data structures with fields suitable for describing a user&#39;s account and information related to a user&#39;s account. When a new object of a particular type is created, the social networking system  630  initializes a new data structure of the corresponding type, assigns a unique object identifier to it, and begins to add data to the object as needed. This might occur, for example, when a user becomes a user of the social networking system  630 , the social networking system  630  generates a new instance of a user profile in the user profile store  636 , assigns a unique identifier to the user account, and begins to populate the fields of the user account with information provided by the user. 
     The connection store  638  includes data structures suitable for describing a user&#39;s connections to other users, connections to external systems  620  or connections to other entities. The connection store  638  may also associate a connection type with a user&#39;s connections, which may be used in conjunction with the user&#39;s privacy setting to regulate access to information about the user. In an embodiment of the invention, the user profile store  636  and the connection store  638  may be implemented as a federated database. 
     Data stored in the connection store  638 , the user profile store  636 , and the activity log  642  enables the social networking system  630  to generate the social graph that uses nodes to identify various objects and edges connecting nodes to identify relationships between different objects. For example, if a first user establishes a connection with a second user in the social networking system  630 , user accounts of the first user and the second user from the user profile store  636  may act as nodes in the social graph. The connection between the first user and the second user stored by the connection store  638  is an edge between the nodes associated with the first user and the second user. Continuing this example, the second user may then send the first user a message within the social networking system  630 . The action of sending the message, which may be stored, is another edge between the two nodes in the social graph representing the first user and the second user. Additionally, the message itself may be identified and included in the social graph as another node connected to the nodes representing the first user and the second user. 
     In another example, a first user may tag a second user in an image that is maintained by the social networking system  630  (or, alternatively, in an image maintained by another system outside of the social networking system  630 ). The image may itself be represented as a node in the social networking system  630 . This tagging action may create edges between the first user and the second user as well as create an edge between each of the users and the image, which is also a node in the social graph. In yet another example, if a user confirms attending an event, the user and the event are nodes obtained from the user profile store  636 , where the attendance of the event is an edge between the nodes that may be retrieved from the activity log  642 . By generating and maintaining the social graph, the social networking system  630  includes data describing many different types of objects and the interactions and connections among those objects, providing a rich source of socially relevant information. 
     The web server  632  links the social networking system  630  to one or more user devices  610  and/or one or more external systems  620  via the network  650 . The web server  632  serves web pages, as well as other web-related content, such as Java, JavaScript, Flash, XML, and so forth. The web server  632  may include a mail server or other messaging functionality for receiving and routing messages between the social networking system  630  and one or more user devices  610 . The messages can be instant messages, queued messages (e.g., email), text and SMS messages, or any other suitable messaging format. 
     The API request server  634  allows one or more external systems  620  and user devices  610  to call access information from the social networking system  630  by calling one or more API functions. The API request server  634  may also allow external systems  620  to send information to the social networking system  630  by calling APIs. The external system  620 , in one embodiment, sends an API request to the social networking system  630  via the network  650 , and the API request server  634  receives the API request. The API request server  634  processes the request by calling an API associated with the API request to generate an appropriate response, which the API request server  634  communicates to the external system  620  via the network  650 . For example, responsive to an API request, the API request server  634  collects data associated with a user, such as the user&#39;s connections that have logged into the external system  620 , and communicates the collected data to the external system  620 . In another embodiment, the user device  610  communicates with the social networking system  630  via APIs in the same manner as external systems  620 . 
     The action logger  640  is capable of receiving communications from the web server  632  about user actions on and/or off the social networking system  630 . The action logger  640  populates the activity log  642  with information about user actions, enabling the social networking system  630  to discover various actions taken by its users within the social networking system  630  and outside of the social networking system  630 . Any action that a particular user takes with respect to another node on the social networking system  630  may be associated with each user&#39;s account, through information maintained in the activity log  642  or in a similar database or other data repository. Examples of actions taken by a user within the social networking system  630  that are identified and stored may include, for example, adding a connection to another user, sending a message to another user, reading a message from another user, viewing content associated with another user, attending an event posted by another user, posting an image, attempting to post an image, or other actions interacting with another user or another object. When a user takes an action within the social networking system  630 , the action is recorded in the activity log  642 . In one embodiment, the social networking system  630  maintains the activity log  642  as a database of entries. When an action is taken within the social networking system  630 , an entry for the action is added to the activity log  642 . The activity log  642  may be referred to as an action log. 
     Additionally, user actions may be associated with concepts and actions that occur within an entity outside of the social networking system  630 , such as an external system  620  that is separate from the social networking system  630 . For example, the action logger  640  may receive data describing a user&#39;s interaction with an external system  620  from the web server  632 . In this example, the external system  620  reports a user&#39;s interaction according to structured actions and objects in the social graph. 
     Other examples of actions where a user interacts with an external system  620  include a user expressing an interest in an external system  620  or another entity, a user posting a comment to the social networking system  630  that discusses an external system  620  or a web page  622   a  within the external system  620 , a user posting to the social networking system  630  a Uniform Resource Locator (URL) or other identifier associated with an external system  620 , a user attending an event associated with an external system  620 , or any other action by a user that is related to an external system  620 . Thus, the activity log  642  may include actions describing interactions between a user of the social networking system  630  and an external system  620  that is separate from the social networking system  630 . 
     The authorization server  644  enforces one or more privacy settings of the users of the social networking system  630 . A privacy setting of a user determines how particular information associated with a user can be shared. The privacy setting comprises the specification of particular information associated with a user and the specification of the entity or entities with whom the information can be shared. Examples of entities with which information can be shared may include other users, applications, external systems  620 , or any entity that can potentially access the information. The information that can be shared by a user comprises user account information, such as profile photos, phone numbers associated with the user, user&#39;s connections, actions taken by the user such as adding a connection, changing user profile information, and the like. 
     The privacy setting specification may be provided at different levels of granularity. For example, the privacy setting may identify specific information to be shared with other users; the privacy setting identifies a work phone number or a specific set of related information, such as, personal information including profile photo, home phone number, and status. Alternatively, the privacy setting may apply to all the information associated with the user. The specification of the set of entities that can access particular information can also be specified at various levels of granularity. Various sets of entities with which information can be shared may include, for example, all friends of the user, all friends of friends, all applications, or all external systems  620 . One embodiment allows the specification of the set of entities to comprise an enumeration of entities. For example, the user may provide a list of external systems  620  that are allowed to access certain information. Another embodiment allows the specification to comprise a set of entities along with exceptions that are not allowed to access the information. For example, a user may allow all external systems  620  to access the user&#39;s work information, but specify a list of external systems  620  that are not allowed to access the work information. Certain embodiments call the list of exceptions that are not allowed to access certain information a “block list”. External systems  620  belonging to a block list specified by a user are blocked from accessing the information specified in the privacy setting. Various combinations of granularity of specification of information, and granularity of specification of entities, with which information is shared are possible. For example, all personal information may be shared with friends whereas all work information may be shared with friends of friends. 
     The authorization server  644  contains logic to determine if certain information associated with a user can be accessed by a user&#39;s friends, external systems  620 , and/or other applications and entities. The external system  620  may need authorization from the authorization server  644  to access the user&#39;s more private and sensitive information, such as the user&#39;s work phone number. Based on the user&#39;s privacy settings, the authorization server  644  determines if another user, the external system  620 , an application, or another entity is allowed to access information associated with the user, including information about actions taken by the user. 
     In some embodiments, the social networking system  630  can include a content provider module  646 . The content provider module  646  can, for example, be implemented as the content provider module  102  of  FIG. 1 . As discussed previously, it should be appreciated that there can be many variations or other possibilities. 
     Hardware Implementation 
     The foregoing processes and features can be implemented by a wide variety of machine and computer system architectures and in a wide variety of network and computing environments.  FIG. 7  illustrates an example of a computer system  700  that may be used to implement one or more of the embodiments described herein in accordance with an embodiment of the invention. The computer system  700  includes sets of instructions for causing the computer system  700  to perform the processes and features discussed herein. The computer system  700  may be connected (e.g., networked) to other machines. In a networked deployment, the computer system  700  may operate in the capacity of a server machine or a client machine in a client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. In an embodiment of the invention, the computer system  700  may be the social networking system  630 , the user device  610 , and the external system  720 , or a component thereof. In an embodiment of the invention, the computer system  700  may be one server among many that constitutes all or part of the social networking system  630 . 
     The computer system  700  includes a processor  702 , a cache  704 , and one or more executable modules and drivers, stored on a computer-readable medium, directed to the processes and features described herein. Additionally, the computer system  700  includes a high performance input/output (I/O) bus  706  and a standard I/O bus  708 . A host bridge  710  couples processor  702  to high performance I/O bus  706 , whereas I/O bus bridge  712  couples the two buses  706  and  708  to each other. A system memory  714  and one or more network interfaces  716  couple to high performance I/O bus  706 . The computer system  700  may further include video memory and a display device coupled to the video memory (not shown). Mass storage  718  and I/O ports  720  couple to the standard I/O bus  708 . The computer system  700  may optionally include a keyboard and pointing device, a display device, or other input/output devices (not shown) coupled to the standard I/O bus  708 . Collectively, these elements are intended to represent a broad category of computer hardware systems, including but not limited to computer systems based on the x86-compatible processors manufactured by Intel Corporation of Santa Clara, Calif., and the x86-compatible processors manufactured by Advanced Micro Devices (AMD), Inc., of Sunnyvale, Calif., as well as any other suitable processor. 
     An operating system manages and controls the operation of the computer system  700 , including the input and output of data to and from software applications (not shown). The operating system provides an interface between the software applications being executed on the system and the hardware components of the system. Any suitable operating system may be used, such as the LINUX Operating System, the Apple Macintosh Operating System, available from Apple Computer Inc. of Cupertino, Calif., UNIX operating systems, Microsoft® Windows® operating systems, BSD operating systems, and the like. Other implementations are possible. 
     The elements of the computer system  700  are described in greater detail below. In particular, the network interface  716  provides communication between the computer system  700  and any of a wide range of networks, such as an Ethernet (e.g., IEEE 802.3) network, a backplane, etc. The mass storage  718  provides permanent storage for the data and programming instructions to perform the above-described processes and features implemented by the respective computing systems identified above, whereas the system memory  714  (e.g., DRAM) provides temporary storage for the data and programming instructions when executed by the processor  702 . The I/O ports  720  may be one or more serial and/or parallel communication ports that provide communication between additional peripheral devices, which may be coupled to the computer system  700 . 
     The computer system  700  may include a variety of system architectures, and various components of the computer system  700  may be rearranged. For example, the cache  704  may be on-chip with processor  702 . Alternatively, the cache  704  and the processor  702  may be packed together as a “processor module”, with processor  702  being referred to as the “processor core”. Furthermore, certain embodiments of the invention may neither require nor include all of the above components. For example, peripheral devices coupled to the standard I/O bus  708  may couple to the high performance I/O bus  706 . In addition, in some embodiments, only a single bus may exist, with the components of the computer system  700  being coupled to the single bus. Moreover, the computer system  700  may include additional components, such as additional processors, storage devices, or memories. 
     In general, the processes and features described herein may be implemented as part of an operating system or a specific application, component, program, object, module, or series of instructions referred to as “programs”. For example, one or more programs may be used to execute specific processes described herein. The programs typically comprise one or more instructions in various memory and storage devices in the computer system  700  that, when read and executed by one or more processors, cause the computer system  700  to perform operations to execute the processes and features described herein. The processes and features described herein may be implemented in software, firmware, hardware (e.g., an application specific integrated circuit), or any combination thereof. 
     In one implementation, the processes and features described herein are implemented as a series of executable modules run by the computer system  700 , individually or collectively in a distributed computing environment. The foregoing modules may be realized by hardware, executable modules stored on a computer-readable medium (or machine-readable medium), or a combination of both. For example, the modules may comprise a plurality or series of instructions to be executed by a processor in a hardware system, such as the processor  702 . Initially, the series of instructions may be stored on a storage device, such as the mass storage  718 . However, the series of instructions can be stored on any suitable computer readable storage medium. Furthermore, the series of instructions need not be stored locally, and could be received from a remote storage device, such as a server on a network, via the network interface  716 . The instructions are copied from the storage device, such as the mass storage  718 , into the system memory  714  and then accessed and executed by the processor  702 . In various implementations, a module or modules can be executed by a processor or multiple processors in one or multiple locations, such as multiple servers in a parallel processing environment. 
     Examples of computer-readable media include, but are not limited to, recordable type media such as volatile and non-volatile memory devices; solid state memories; floppy and other removable disks; hard disk drives; magnetic media; optical disks (e.g., Compact Disk Read-Only Memory (CD ROMS), Digital Versatile Disks (DVDs)); other similar non-transitory (or transitory), tangible (or non-tangible) storage medium; or any type of medium suitable for storing, encoding, or carrying a series of instructions for execution by the computer system  700  to perform any one or more of the processes and features described herein. 
     For purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the description. It will be apparent, however, to one skilled in the art that embodiments of the disclosure can be practiced without these specific details. In some instances, modules, structures, processes, features, and devices are shown in block diagram form in order to avoid obscuring the description. In other instances, functional block diagrams and flow diagrams are shown to represent data and logic flows. The components of block diagrams and flow diagrams (e.g., modules, blocks, structures, devices, features, etc.) may be variously combined, separated, removed, reordered, and replaced in a manner other than as expressly described and depicted herein. 
     Reference in this specification to “one embodiment”, “an embodiment”, “other embodiments”, “one series of embodiments”, “some embodiments”, “various embodiments”, or the like means that a particular feature, design, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. The appearances of, for example, the phrase “in one embodiment” or “in an embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, whether or not there is express reference to an “embodiment” or the like, various features are described, which may be variously combined and included in some embodiments, but also variously omitted in other embodiments. Similarly, various features are described that may be preferences or requirements for some embodiments, but not other embodiments. 
     The language used herein has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.