Patent Publication Number: US-2019188320-A1

Title: Systems and methods for providing ephemeral content items created from live stream videos

Description:
FIELD OF THE INVENTION 
     The present technology relates to the field of social networks. More particularly, the present technology relates to providing ephemeral content associated with social networking systems. 
     BACKGROUND 
     Today, people often utilize computing devices (or systems) for a wide variety of purposes. Users can use their computing devices, for example, to interact with one another, create content, share content, and view content. In some cases, a user can utilize his or her computing device to access a social networking system (or service). The user can provide, post, share, and access various content items, such as status updates, images, videos, articles, and links, via the social networking system. 
     A social networking system may provide resources through which users may publish content items. In one example, a content item can be presented on a profile page of a user. As another example, a content item can be presented through a feed for a user to access. In some embodiments, a content item can be a live stream video. 
     SUMMARY 
     Various embodiments of the present disclosure can include systems, methods, and non-transitory computer readable media configured to generate an ephemeral content item from a live stream video that has concluded, wherein the ephemeral content item from the live stream video is included in an ephemeral content item collection. A plurality of ephemeral content item collections, including the ephemeral content item collection, can be ranked based on a machine learning model. At least one of the ranked plurality of ephemeral content item collections is provided in an ephemeral content feed of a user. 
     In some embodiments, the generating an ephemeral content item from the live stream video includes dividing the live stream video into a plurality of chunks. 
     In certain embodiments, each of the plurality of ephemeral content item collections is associated with a type of ephemeral content item collection, wherein the type of ephemeral content item collection is selected from one or more of: a post-live ephemeral content item collection or a non-post-live ephemeral content item collection. 
     In an embodiment, the machine learning model is trained based on features relating to one or more of: ephemeral content item collection attributes, ephemeral content item attributes, or user attributes. 
     In some embodiments, the ephemeral content item collection attributes include one or more of: the type of ephemeral content item collection, an amount of time a user spent on an ephemeral content item collection, an aggregate or average amount of time a user spent on ephemeral content item collections, or a number of skips associated with an ephemeral content item collection. 
     In certain embodiments, the ephemeral content item attributes include one or more of: a type of ephemeral content item, an amount of time a user spent on an ephemeral content item, an aggregate or average amount of time a user spent on ephemeral content items, or a number of skips associated with an ephemeral content item. 
     In an embodiment, each of the plurality of ephemeral content item collections includes one or more ephemeral content items, wherein each ephemeral content item is associated with a type of ephemeral content item, wherein the type of ephemeral content item is selected from one or more of: a post-live ephemeral content item or a non-post-live ephemeral content item. 
     In some embodiments, the machine learning model is trained to predict a likelihood of a user engaging with an ephemeral content item collection. 
     In certain embodiments, a total number of views associated with the live stream video includes a number of views of the ephemeral content item generated from the live stream video. 
     In an embodiment, feedback associated with the live stream video is presented during playback of the ephemeral content item generated from the live stream video. 
     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 ephemeral content ranking module configured to rank ephemeral content, according to an embodiment of the present disclosure. 
         FIG. 2  illustrates an example content item collection ranking module configured to rank ephemeral content item collections, according to an embodiment of the present disclosure. 
         FIG. 3A  illustrates an example scenario for ranking ephemeral content item collections, according to an embodiment of the present disclosure. 
         FIG. 3B  illustrates an example scenario for providing post-live ephemeral content item collections, according to an embodiment of the present disclosure. 
         FIG. 4  illustrates an example first method for ranking ephemeral content item collections, according to an embodiment of the present disclosure. 
         FIG. 5  illustrates an example second method for ranking ephemeral content item collections, according to an embodiment of the present disclosure. 
         FIG. 6  illustrates a network diagram of an example 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 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 
     Providing Ephemeral Content Items Created from Live Stream Videos 
     People use computing devices (or systems) for a wide variety of purposes. Computing devices can provide different kinds of functionality. Users can utilize their computing devices to produce information, access information, and share information. In some cases, users can utilize computing devices to interact or engage with a conventional social networking system (e.g., a social networking service, a social network, etc.). A social networking system may provide resources through which users may publish content items. In one example, a content item can be presented on a profile page of a user. As another example, a content item can be presented through a feed for a user to access. 
     Conventional approaches specifically arising in the realm of computer technology can provide live stream videos. For example, a user can start recording a video and broadcast the video in real time to other users. Under conventional approaches, a live stream video may expire or no longer be accessible after the live stream video ends. However, users may want to access content of the live stream video even after the live stream video ends. 
     An improved approach rooted in computer technology can overcome the foregoing and other disadvantages associated with conventional approaches specifically arising in the realm of computer technology. Based on computer technology, the disclosed technology can create an ephemeral content item from a live stream video after the live stream video ends. For example, the live stream video by a user can be converted to an ephemeral content item and can be included in an ephemeral content item collection. An ephemeral content item may expire after a predetermined time period. In some embodiments, an ephemeral content item that is created from a live stream video can be referred to as a “post-live ephemeral content item.” Similarly, an ephemeral content item collection including a post-live ephemeral content item can be referred to as a “post-live ephemeral content item collection.” A post-live ephemeral content item collection can be considered a type of ephemeral content item collection and can be ranked along with other types of ephemeral content item collections for inclusion in an ephemeral content feed of a user. For example, post-live ephemeral content item collections and other types of ephemeral content item collections can be ranked based on machine learning techniques. In some embodiments, a machine learning model can be trained to rank post-live ephemeral content item collections and other ephemeral content item collections based on features relating to user attributes, ephemeral content item collection attributes, and ephemeral content item attributes. In this manner, the disclosed technology can provide access to content of live stream videos for a predetermined time period after the live stream videos have ended. Additional details relating to the disclosed technology are provided below. 
       FIG. 1  illustrates an example system  100  including an example ephemeral content ranking module  102  configured to rank ephemeral content, according to an embodiment of the present disclosure. The ephemeral content ranking module  102  can include a post-live ephemeral content provision module  104  and an ephemeral content item collection ranking module  106 . In some instances, the example system  100  can include at least one data store  120 . The components (e.g., modules, elements, steps, blocks, 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 various embodiments, one or more of the functionalities described in connection with the ephemeral content ranking module  102  can be implemented in any suitable combinations. While the disclosed technology is described in connection with live stream videos and ephemeral content associated with a social networking system for illustrative purposes, the disclosed technology can apply to any other type of system and/or content. 
     Ephemeral content can refer to any type of content that is accessible only for a predetermined time period (e.g., second(s), minute(s), hour(s), day(s), etc.) or for a predetermined number of times (e.g., once, twice, etc.). For example, ephemeral content can expire after the predetermined time period passes or upon viewing by a user. In some instances, ephemeral content may be removed from servers and/or storage devices after expiration so that they are not accessible after their expiration. Examples of ephemeral content can include images, videos, audio, etc. As used herein, any content that is not ephemeral content can be referred to as non-ephemeral content. An ephemeral content item can refer to a content item that is ephemeral. One or more ephemeral content items created by users can be organized as or in ephemeral content item collections. An ephemeral content item collection can include one or more ephemeral content items and can be referred to as a “story.” In some embodiments, ephemeral content items of an ephemeral content item collection can be collectively referred to as a “reel.” For instance, ephemeral content items of an ephemeral content item collection can be considered to constitute a reel of the ephemeral content item collection. An ephemeral content item collection may be associated with a particular user, and can include one or more ephemeral content items created by the particular user. In some embodiments, an ephemeral content item collection may be associated with a subject matter or a topic, rather than a particular user, and the ephemeral content item collection can include one or more ephemeral content items from different users that relate to the topic. There can be many different types of ephemeral content item collections. 
     The post-live ephemeral content provision module  104  can provide ephemeral content items and/or ephemeral content item collections, including post-live ephemeral content items and/or post-live ephemeral content item collections. In some embodiments, an ephemeral content item can be created from a live stream video that has ended. Users may record and broadcast live stream videos using computing devices. Live stream videos may be provided through a social networking system in which the ephemeral content ranking module  102  is implemented. A live stream video can be in any format. For example, a live stream video can be two-dimensional (2D) media content or three-dimension (3D) media content. Examples of a live stream video can include a 2D video and a 360 video, among others. A user can begin recording a live stream video and transmit the live stream video in real time to a server associated with the social networking system. The server associated with the social networking system can in turn transmit the live stream video to one or more other users. For instance, the other users may view the live stream video in a user interface associated with the social networking system. The live stream video may end or complete when the user stops recording and transmitting the live stream video. The live stream video that has ended may be stored on or saved to storage associated with the social networking system. As discussed herein, a live stream video that has ended or completed can be referred to as a “completed live stream video.” As discussed herein, an ephemeral content item created or generated from a completed live stream video can be referred to as a “post-live ephemeral content item,” and an ephemeral content item that is not a post-live ephemeral content item can be referred to as a “regular ephemeral content item” or a “non-post-live ephemeral content item.” Also as discussed herein, an ephemeral content item collection that includes post-live ephemeral content items can be referred to as a “post-live ephemeral content item collection,” and an ephemeral content item collection that includes non-post-live ephemeral content items can be referred to as a “regular ephemeral content item collection” or a “non-post-live ephemeral content item collection.” For instance, a post-live ephemeral content item collection can include only post-live ephemeral content item collections, and a non-post-live ephemeral content item collection can include only non-post-live ephemeral content item collections. A non-post-live ephemeral content item collection and a post-live ephemeral content item collection can each be considered to be a type of ephemeral content item collection. 
     The post-live ephemeral content provision module  104  can create a post-live ephemeral content item from a completed live stream video. For example, the post-live ephemeral content provision module  104  can convert a completed live stream video to a post-live ephemeral content item. A user associated with a live stream video may be presented with an option to create a post-live ephemeral content item from the live stream video after the live stream video ends, and a corresponding post-live ephemeral content item can be created in response to selection of the option by the user. As an example, the user may be presented with a “share” option to create a post-live ephemeral content item from the live stream video and a “delete” or “discard” option to delete the live stream video without creating a post-live ephemeral content item. As another example, the user may be presented with a “share” option as a default for all live stream videos, and a toggle can be provided to switch the default to a “delete” or “discard” option. Many variations are possible. In some embodiments, when a completed live stream video is converted to a post-live ephemeral content item collection, the live stream video can be divided into multiple chunks or portions in order to facilitate viewing of the live stream video by users. For instance, the duration of live stream videos may generally be longer than the duration of typical ephemeral content items, and dividing a live stream video into multiple chunks can make it easier for a user to navigate within the live stream video. In some embodiments, a post-live ephemeral content item collection can be created to include one or more post-live ephemeral content item collections of a user. For example, a post-live ephemeral content item collection can be associated with a particular user and include post-live ephemeral content items of the particular user. The post-live ephemeral content item collection of the particular user can be separate from a non-post-live ephemeral content item collection of the particular user, which can include non-post-live ephemeral content items of the particular user. Accordingly, a particular user can be potentially associated with two (or more) different ephemeral content item collections. In some embodiments, both post-live ephemeral content items and non-post-live ephemeral content items can be included in the same ephemeral content item collection, and there can be one ephemeral content item collection for a particular user. A view count or a total number of views of a live stream video can include a total number of views during broadcast of the live stream video as well as a number of views of a post-live ephemeral content item created from the live stream video. 
     The post-live ephemeral content provision module  104  can provide ephemeral content item collections via an ephemeral content feed of a user. For example, an ephemeral content feed can be presented in a region of a user interface of a computing device running an application associated with the social networking system. A user who is associated with an ephemeral content item collection or creates an ephemeral content item included in an ephemeral content item collection can be referred to as an “authoring user.” A user who has access to an ephemeral content item collection and/or an ephemeral content item in an ephemeral content feed can be referred to as a “viewing user.” Various ephemeral content item collections can be provided in an ephemeral content feed of a viewing user. For example, the ephemeral content feed of the viewing user can include one or more non-post-live ephemeral content item collections and one or more post-live ephemeral content item collections. The ephemeral content feed of the viewing user can also include a non-post-live ephemeral content item collection and/or a post-live ephemeral content item collection of the viewing user. An ephemeral content item collection can appear or be accessible in an ephemeral content feed until all ephemeral content items included in the ephemeral content item collection expire. In some embodiments, an ephemeral content item collection can appear or be accessible in an ephemeral content feed for a predetermined time period (e.g., second(s), minute(s), hour(s), day(s), etc.). In some embodiments, the ephemeral content feed of the viewing user may display a predetermined number of ephemeral content item collections, and additional ephemeral content item collections can be displayed in response to navigation by the viewing user. For example, the viewing user can scroll through the ephemeral content feed to selectively access more ephemeral content item collections. 
     The post-live ephemeral content provision module  104  can provide ephemeral content item collections using various representations. For example, an ephemeral content item collection can be represented in a user interface by an avatar of a user, an icon, an image, an animation, a video, etc. In some embodiments, a representation of a post-live ephemeral content item collection can be based on a representation of a non-post-live ephemeral content item collection, but have a distinguishing feature to differentiate the representation of a post-live ephemeral content item collection from the representation of a non-post-live ephemeral content item collection. As an example, the representation of a non-post-live ephemeral content item collection of a user can be an avatar of the user, and the representation of a post-live ephemeral content item collection of the user can be the avatar of the user with an icon or badge showing a play button. In some embodiments, a representation of an ephemeral content item collection may appear to be faded or have a different appearance after a viewing user navigates through or views all ephemeral content items of the ephemeral content item collection. Many variations are possible. 
     A viewing user can engage with an ephemeral content item collection in the viewing user&#39;s ephemeral content feed by selecting the ephemeral content item collection. Ephemeral content items of an ephemeral content item collection can be accessed upon selecting the ephemeral content item collection. A viewing user can select an ephemeral content item collection in various manners, for example, by a click, a touch gesture, etc. An immersive viewer can be provided in a user interface displaying the viewing user&#39;s ephemeral content feed, and the viewing user can view ephemeral content items of ephemeral content item collections. If a viewing user selects an ephemeral content item collection in the viewing user&#39;s ephemeral content feed, the immersive viewer can be launched and initiate playback of the selected ephemeral content item collection. One or more ephemeral content items of the selected ephemeral content item collection can be played back. If playback of the selected ephemeral content item collection ends, playback of another ephemeral content item collection can start. Playback of ephemeral content item collections within the immersive viewer can be performed based on an order or sequence of playback. The viewing user may transition within the immersive viewer between ephemeral content item collections and/or ephemeral content items displayed in the viewing user&#39;s ephemeral content feed. For example, the viewing user may skip or abandon an ephemeral content item collection and/or an ephemeral content item before playback of the ephemeral content item collection and/or the ephemeral content item ends. 
     The post-live ephemeral content provision module  104  can provide post-live ephemeral content items of a post-live ephemeral content item collection for playback within an immersive viewer. The immersive viewer can also include user interface (UI) elements to allow a viewing user to navigate between multiple post-live ephemeral content items. Examples of UI elements can include buttons, images, icons, etc. As an example, the immersive viewer can include arrows, such as a back arrow and a forward arrow, to transition between multiple post-live ephemeral content items, and the viewing user can transition between the multiple post-live ephemeral content items by selecting the arrows. The immersive viewer can also allow a viewing user to navigate through a post-live ephemeral content item by performing an appropriate action, such as a click, a touch gesture, a selection of a UI element, etc. For instance, the viewing user may transition between chunks of the post-live ephemeral content item by a click, a touch gesture, or selection of a UI element. In some embodiments, a touch gesture can be a tap. A viewing user may skip or abandon a chunk of a post-live ephemeral content item by transitioning to another chunk or another post-live ephemeral content item before playback of the chunk or the post-live ephemeral content item ends. In some embodiments, a completed live stream video associated with a post-live ephemeral content item may have received feedback from users in real time during its live broadcast. Examples of feedback can include likes, comments, etc. Any such feedback can be provided during playback of the post-live ephemeral content item associated with the completed live stream video such that a viewing user can have an experience during playback that is similar to viewing the live version of the completed live stream video. For example, feedback provided during live broadcast of the completed live stream video can be associated with timestamps, and such feedback can be provided during playback of the post-live ephemeral content item based on corresponding timestamps of the post-live ephemeral content item. All examples herein are provided for illustrative purposes, and there can be many variations and other possibilities. 
     The ephemeral content item collection ranking module  106  can rank ephemeral content item collections based on various techniques. In some embodiments, the ephemeral content item collection ranking module  106  can rank ephemeral content item collections based on one or more machine learning models. Functionality of the ephemeral content item collection ranking module  106  is described in more detail herein. 
     In some embodiments, the ephemeral content ranking 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 ephemeral content ranking module  102  can be, in part or in whole, implemented as software running on one or more computing devices or systems, such as on a server system or a client computing device. In some instances, the ephemeral content ranking module  102  can be, in part or in whole, implemented within or configured to operate in conjunction or be integrated with a social networking system (or service), such as a social networking system  630  of  FIG. 6 . Likewise, in some instances, the ephemeral content ranking module  102  can be, in part or in whole, implemented within or configured to operate in conjunction or be integrated with a client computing device, such as the user device  610  of  FIG. 6 . For example, the ephemeral content ranking module  102  can be implemented as or within a dedicated application (e.g., app), a program, or an applet running on a user computing device or client computing system. The application incorporating or implementing instructions for performing functionality of the ephemeral content ranking module  102  can be created by a developer. The application can be provided to or maintained in a repository. In some cases, the application can be uploaded or otherwise transmitted over a network (e.g., Internet) to the repository. For example, a computing system (e.g., server) associated with or under control of the developer of the application can provide or transmit the application to the repository. The repository can include, for example, an “app” store in which the application can be maintained for access or download by a user. In response to a command by the user to download the application, the application can be provided or otherwise transmitted over a network from the repository to a computing device associated with the user. For example, a computing system (e.g., server) associated with or under control of an administrator of the repository can cause or permit the application to be transmitted to the computing device of the user so that the user can install and run the application. The developer of the application and the administrator of the repository can be different entities in some cases, but can be the same entity in other cases. It should be understood that many variations are possible. 
     The data store  120  can be configured to store and maintain various types of data, such as the data relating to support of and operation of the ephemeral content ranking module  102 . The data maintained by the data store  120  can include, for example, information relating to live stream videos, ephemeral content, ephemeral content feeds, ephemeral content item collections, ephemeral content items, post-live ephemeral content item collections, post-live ephemeral content items, machine learning models, ranking data, etc. The data store  120  also can maintain other information associated with a social networking system. The information associated with the social networking system can include data about users, social connections, social interactions, locations, geo-fenced areas, maps, places, events, groups, posts, communications, content, account settings, privacy settings, and a social graph. The social graph can reflect all entities of the social networking system and their interactions. As shown in the example system  100 , the ephemeral content ranking module  102  can be configured to communicate and/or operate with the data store  120 . In some embodiments, the data store  120  can be a data store within a client computing device. In some embodiments, the data store  120  can be a data store of a server system in communication with the client computing device. 
       FIG. 2  illustrates an example ephemeral content item collection ranking module  202  configured to rank ephemeral content item collections, according to an embodiment of the present disclosure. In some embodiments, the ephemeral content item collection ranking module  106  of  FIG. 1  can be implemented with the example ephemeral content item collection ranking module  202 . As shown in the example of  FIG. 2 , the example ephemeral content item collection ranking module  202  can include a machine learning training module  204  and a machine learning evaluation module  206 . 
     The ephemeral content item collection ranking module  202  can rank ephemeral content item collections that are candidates for inclusion in a viewing user&#39;s ephemeral content feed. For example, the ephemeral content item collection ranking module  202  can rank ephemeral content item collections to predict a likelihood of a viewing user engaging with ephemeral content item collections. A score can be determined for each ephemeral content item collection, and the score can be indicative of a likelihood of a viewing user engaging with the ephemeral content item collection. The ephemeral content item collection ranking module  202  can rank ephemeral content item collections based on their respective scores. The ephemeral content item collection ranking module  202  can rank different types of ephemeral content item collections, such as non-post-live ephemeral content item collections and post-live ephemeral content item collections. One or more ranked ephemeral content item collections can be provided in an ephemeral content feed based on an order of ranking. 
     The ephemeral content item collection ranking module  202  can predict a likelihood of a viewing user engaging with an ephemeral content item collection in various ways. For example, the likelihood of a viewing user engaging with an ephemeral content item collection can be determined based on a probability of or relating to a viewing user spending time on an ephemeral content item collection, a probability of a viewing user selecting an ephemeral content item collection, etc. The probability of a viewing user spending time on an ephemeral content item collection can be denoted as P(time). For example, the viewing user can spend time on the ephemeral content item collection by viewing one or more ephemeral content items of the ephemeral content item collection in an immersive viewer. As such, the probability of the viewing user spending time on the ephemeral content item collection can be considered to be a probability of the viewing user spending time on one or more ephemeral content items of the ephemeral content item collection within the immersive viewer. In some embodiments, P(time) can be described in terms of an estimated amount of time the viewing user is likely to spend on the ephemeral content item collection. For instance, P(time) can be specified in a unit of time, such as second(s), minute(s), hour(s), etc. In other embodiments, P(time) can be described in terms of whether the viewing user is likely to spend a threshold amount of time on the ephemeral content item collection. The probability of a viewing user selecting an ephemeral content item collection can be denoted as P(select). In some embodiments, the likelihood of a viewing user engaging with an ephemeral content item collection can be determined based on P(time), P(select), or any combination thereof, as well as other relevant factors. Many variations are possible. 
     The machine learning training module  204  can train a machine learning model to rank ephemeral content item collections for a viewing user&#39;s ephemeral content feed. The machine learning training module  204  can train a machine learning model to rank various types of ephemeral content item collections, including non-post-live ephemeral content item collections and post-live ephemeral content item collections. For instance, the machine learning training module  204  can train a machine learning model to predict a likelihood of a viewing user engaging with an ephemeral content item collection. As an example, the machine learning model can be trained to determine scores of ephemeral content item collections based on P(time). As another example, the machine learning model can be trained to determine scores of ephemeral content item collections based on P(select). As a further example, the machine learning model can be trained to determine scores of ephemeral content item collections based on any combination of P(time) and P(select), such as a sum, a product, etc. Many variations are possible. 
     The machine learning training module  204  can train a machine learning model to rank ephemeral content item collections based on training data. The training data can include various features. For example, features can relate to ephemeral content item collection attributes, ephemeral content item attributes, user attributes, etc. 
     Ephemeral content item collection attributes can include any attributes associated with ephemeral content item collections. Examples of ephemeral content item collection attributes can include a type of ephemeral content item collection (e.g., non-post-live, post-live, etc.), an amount of time a viewing user spent on an ephemeral content item collection, an aggregate or average amount of time a viewing user spent on ephemeral content item collections, a number of skips associated with an ephemeral content item collection, whether an ephemeral content item collection has already been viewed by a viewing user, etc. In some embodiments, the amount of time a viewing user spent on an ephemeral content item collection can be determined based on the amount of time a viewing user spent on one or more ephemeral content items of the ephemeral content item collection. The number of skips associated with an ephemeral content item collection can be determined based on a number of skips associated with one or more ephemeral content items of the ephemeral content item collection. The attribute of whether an ephemeral content item collection has already been viewed by a viewing user can indicate whether the viewing user has viewed all ephemeral content items of the ephemeral content item collection. In some embodiments, an ephemeral content item collection that has already been viewed by a viewing user can be ranked lower than ephemeral content item collections that have not been viewed by the viewing user. In some embodiments, ephemeral content item collection attributes can additionally or alternatively include an authoring user of an ephemeral content item collection and/or an ephemeral content item (e.g., an identity of an authoring user), one or more ephemeral content items included in an ephemeral content item collection, a number of ephemeral content items included in an ephemeral content item collection, one or more viewing users of an ephemeral content item collection and/or an ephemeral content item, a rate of selection of an ephemeral content item collection by viewing users, a selection of an ephemeral content item collection by a viewing user, a rate of selection of an ephemeral content item by viewing users, a selection of an ephemeral content item by a viewing user, historical information associated with an ephemeral content item collection, visual characteristics of a representation of an ephemeral content item collection, whether an ephemeral content item collection includes a live ephemeral content item, whether an ephemeral content item collection includes an expiring ephemeral content item, etc. Historical information associated with an ephemeral content item collection can include whether a viewing user has selected an ephemeral content item collection of a particular authoring user at one or more previous times when the ephemeral content item collection of the authoring user was included in the viewing user&#39;s ephemeral content feed, a ranking or position of an ephemeral content item collection of a particular authoring user at one or more previous times when the ephemeral content item collection was included in the viewing user&#39;s ephemeral content feed, etc. Visual characteristics of a representation of an ephemeral content item collection can include a color, one or more objects included in the representation, a subject matter or topic reflected in the representation, etc. 
     Ephemeral content item attributes can include any attributes associated with ephemeral content items. Examples ephemeral content item attributes can include a type of ephemeral content item (e.g., non-post-live, post-live, etc.), an amount of time a viewing user spent on an ephemeral content item, an aggregate or average amount of time a viewing user spent on ephemeral content items, a rate of completion of an ephemeral content item, a number of skips for an ephemeral content item by a viewing user, etc. The rate of completion of an ephemeral content item can indicate a ratio or a percentage of viewing users that completed viewing the ephemeral content item. The number of skips for an ephemeral content item by a viewing user can indicate a number of times the viewing user transitioned to another ephemeral content item or another portion within an ephemeral content item, such as a chunk. For example, for a post-live ephemeral content item, the associated completed live stream video can be much longer in duration than a typical ephemeral content item, such as an image or a short video. Accordingly, a viewing user may skip through a large number of chunks of the post-live ephemeral content item. The number of skips for an ephemeral content item can be indicative of a quality of an ephemeral content item or an interest of a viewing user in the ephemeral content item. For instance, the number of skips for an ephemeral content item can be inversely related to the quality of the ephemeral content item or the interest of a viewing user in the ephemeral content item. If the number of skips by a viewing user for a particular ephemeral content item is high, it can indicate that the quality of the ephemeral content item was low and the viewing user was not very interested in the ephemeral content item. Examples of ephemeral content item attributes can also include content attributes, such as a type of media (e.g., an image, a video, an audio, etc.), a length of content, a subject matter or topic, one or more objects represented in content, a popularity of content (e.g., many users engaging with content), etc. 
     User attributes can include any attributes associated with users. User attributes can include attributes associated with authoring users and attributes associated with viewing users. Examples of user attributes can include a location (e.g., a country, state, county, city, etc.), an age, an age range, a gender, a language, a number of connections (e.g., friends or followers), an interest (e.g., topics in which a user has expressed interest), a computing device, an operating system (OS), etc. User attributes can also include attributes associated with connections between authoring users and viewing users. For example, a user can be a connection of another user (e.g., a friend or a follower), and a coefficient or weight can be associated with the connection. The coefficient can be indicative of a strength of the connection. In some embodiments, a connection between two users is two-way such that when the connection is established between a first user and a second user, the two users are connections of each other. In other embodiments, a connection between two users can be one-way such that a first user is a connection of a second user, but the second user is not a connection of the first user. In these embodiments, users can be subscribers or followers of other users. User attributes can further include attributes associated with interactions between authoring users and viewing users. Examples of interactions between authoring users and viewing users can include whether a viewing user liked a content item in an authoring user&#39;s feed or profile, whether a viewing user sent a direct message to an authoring user, etc. Many variations are possible. 
     In some embodiments, values of features can be tracked or maintained separately for different types of ephemeral content item collections and/or ephemeral content items. For instance, values of features can be tracked separately for non-post-live ephemeral content item collections and post-live ephemeral content item collections. Similarly, values of features can be tracked separately for non-post-live ephemeral content items and post-live ephemeral content items. As an example, values of a feature relating to an amount of time a viewing user spent on an ephemeral content item collection can separately reflect an amount of time a viewing user spent on post-live ephemeral content item collections and an amount of time a viewing user spent on non-post-live ephemeral content item collections. As another example, values of a feature relating to an amount of time a viewing user spent on an ephemeral content item can separately reflect an amount of time a viewing user spent on post-live ephemeral content items and an amount of time a viewing user spent on non-post-live ephemeral content items. In certain embodiments, a feature can be based on aggregate or average values of another feature for different types of ephemeral content item collections and/or ephemeral content items. For instance, the feature can be a ratio of or a comparison between the aggregate or averages values of the other feature for different types of ephemeral content item collections and/or ephemeral content items. For example, a feature can be a ratio of an average value of an amount of time spent by a viewing user on non-post-live ephemeral content items and an average value of an amount of time spent by a viewing user on post-live ephemeral content items. In some embodiments, there can be features relating to ephemeral content item attributes that are specific to a particular type of ephemeral content item. For instance, since non-post-live ephemeral content items can be not long enough in duration for a viewing user to skip multiple times, a number of skips associated with an ephemeral content item may only be applicable to post-live ephemeral content items. Many variations are possible. 
     The training data can include various labels. The labels can include labels indicating whether viewing users selected ephemeral content item collections, labels indicating whether viewing users spent time on ephemeral content item collections and/or ephemeral content items, labels indicating an amount of time viewing users spent on ephemeral content item collections and/or ephemeral content items, and/or labels indicating whether viewing users spent a threshold amount of time on ephemeral content item collections and/or ephemeral content items. 
     The machine learning training module  204  can determine weights associated with various features used to train a machine learning model based on, for example, regression techniques. In some embodiments, the machine learning model can be a neural network. The machine learning training module  204  can determine which features are most effective in predicting engagement with ephemeral content item collections by viewing users. Accordingly, features for training the machine learning model can vary for different types of ephemeral content item collections, such as non-post-live ephemeral content item collections and post-live ephemeral content item collections. 
     The machine learning evaluation module  206  can apply the trained machine learning model to rank ephemeral content item collections for a viewing user&#39;s ephemeral content feed. For example, the trained machine learning model can be applied to feature data relating to an ephemeral content item collection, one or more ephemeral content items of the ephemeral content item collection, and a viewing user to determine a score for the ephemeral content item collection. Ephemeral content item collections can be ordered according to their respective scores. In some embodiments, an ephemeral content item collection can be provided in the ephemeral content feed if the score for the ephemeral content item collection satisfies a threshold value. In other embodiments, a predetermined number of top ranked ephemeral content item collections can be provided in the ephemeral content feed. In some embodiments, the machine learning evaluation module  206  can rank ephemeral content item collections for a viewing user&#39;s ephemeral content feed each time the ephemeral content feed is refreshed. In these embodiments, ephemeral content item collections and/or ordering of ephemeral content item collections displayed to the viewing user may change each time. One or more machine learning models discussed in connection with the ephemeral content ranking module  102  and its components can be implemented separately or in combination, for example, as a single machine learning model, as multiple machine learning models, as one or more staged machine learning models, as one or more combined machine learning models, etc. 
     In some embodiments, the ephemeral content item collection ranking module  202  may not distinguish between non-post-live ephemeral content item collections and post-live ephemeral content item collections when ranking ephemeral content item collections. For example, a machine learning model can be trained to predict a likelihood of a viewing user engaging with ephemeral content item collections without considering the type of ephemeral content item collection. However, ranking ephemeral content item collections without considering the type of ephemeral content item collection may overestimate a likelihood of a viewing user engaging with a post-live ephemeral content item collection. A post-live ephemeral content item associated with a completed live stream video can generally be longer in duration than a typical ephemeral content item. Accordingly, if an amount of time a viewing user is likely to spend on a post-live ephemeral content item collection or a post-live ephemeral content item is estimated based on a length of a post-live ephemeral content item associated with a completed live stream video, the amount of time may generally be estimated to be longer than an amount of time the viewing user is likely to spend on a typical ephemeral content item. However, viewing users may tend to skip through post-live ephemeral content items due to the longer duration. Therefore, the actual amount of time spent by a viewing user on a post-live ephemeral content item may be much less than the estimated amount of time. Accordingly, an adjustment can be made to an amount of time a viewing user is likely to spend on a post-live ephemeral content item collection or a post-live ephemeral content item, for example, by decreasing the amount of time by a predetermined value. Accordingly, scores of post-live ephemeral content item collections determined based on the machine learning model, which can be based in part on the adjusted amount of time a viewing user is likely to spend on a post-live ephemeral content item collection or a post-live ephemeral content item, can be adjusted to have lower values. The adjustment can be considered a penalty for post-live ephemeral content item collections. In some embodiments, instead of adjusting scores of post-live ephemeral content item collections, a threshold value for providing post-live ephemeral content item collections in an ephemeral content feed can be set to a higher value than a threshold value for providing non-post-live ephemeral content item collections. All examples herein are provided for illustrative purposes, and there can be many variations and other possibilities. 
       FIG. 3A  illustrates an example scenario  300  for ranking ephemeral content item collections, according to an embodiment of the present disclosure. The example scenario  300  illustrates a computing device  302  displaying a user interface  304  associated with a social networking system. The user interface  304  includes an ephemeral content feed  306  of a user, which includes one or more ephemeral content item collections  310 . In the example scenario  300 , the user can be a viewing user, and user-based ephemeral content item collections can be ranked as candidates for inclusion in the user&#39;s ephemeral content feed  306 . The ranking of ephemeral content item collections can be performed by the ephemeral content ranking module  102 , as discussed herein. The user&#39;s ephemeral content feed  306  can include the user&#39;s own non-post-live ephemeral content item collection  310   a  and a predetermined number of top ranked ephemeral content item collections  310   b,    310   c,    310   d.  In the example scenario  300 , the ephemeral content item collections  310   b,    310   c  are non-post-live ephemeral content item collections and the ephemeral content item collection  310   d  is a post-live ephemeral content item collection. In the example of  FIG. 3A , each ephemeral content item collection is represented by an avatar of an associated user. A representation of a post-live ephemeral content item collection, such as the ephemeral content item collection  310   d,  can include a play button to distinguish the post-live ephemeral content item collection from a non-post-live ephemeral content item collection. The user&#39;s ephemeral content feed  306  can be scrolled right in order to show more ephemeral content item collections. The user interface  304  also includes a feed  308  of the user, which can include non-ephemeral content items. All examples herein are provided for illustrative purposes, and there can be many variations and other possibilities. 
       FIG. 3B  illustrates an example scenario  350  for providing post-live ephemeral content item collections, according to an embodiment of the present disclosure. The example scenario  350  illustrates a computing device  352  displaying a user interface  354  associated with a social networking system. The user interface  354  shows an immersive viewer  356  displaying a post-live ephemeral content item  358  of a post-live ephemeral content item collection that has been selected by a viewing user. In the example of  FIG. 3B , the selected post-live ephemeral content item collection can be the ephemeral content item collection  310   d  in  FIG. 3A . The immersive viewer  356  can show an avatar  360  of a user associated with the post-live ephemeral content item  358 . The immersive viewer  356  can also include a UI element  362  for closing or exiting the immersive viewer  356 . The immersive viewer  356  can also include arrows  364   a,    364   b  to transition between multiple post-live ephemeral content items of the selected ephemeral content item collection. For example, the immersive viewer  356  can include a back arrow  364   a  and a forward arrow  364   b.  A completed live stream video associated with the post-live ephemeral content item  358  can be divided into multiple chunks. The immersive viewer  356  can include a representation  366  of the multiple chunks and an indication to a user of their progress in viewing the completed live stream video. In the example of  FIG. 3B , the post-live ephemeral content item  358  includes five chunks, and the immersive viewer  356  is playing back the first of the five chunks. In some embodiments, the representation  366  can be a single bar that represents all chunks of the post-live ephemeral content item  358 , and the progress in viewing the completed live stream video can be indicated in or through the bar. A user may transition between the multiple chunks by a click, a touch gesture, a selection of a UI element, etc. In some embodiments, the touch gesture can be a tap on one or more of the chunks in the representation  366 . The immersive viewer  356  can also include an icon  368  for following or unfollowing the user associated with the post-live ephemeral content item  358  as well as an icon  370  for sending a message to the user. All examples herein are provided for illustrative purposes, and there can be many variations and other possibilities. 
       FIG. 4  illustrates an example first method  400  for ranking ephemeral content item collections, according to an embodiment of the present disclosure. It should be understood that there can be additional, fewer, or alternative steps performed in similar or alternative orders, or in parallel, based on the various features and embodiments discussed herein unless otherwise stated. 
     At block  402 , the example method  400  can generate an ephemeral content item from a live stream video that has concluded, wherein the ephemeral content item from the live stream video is included in an ephemeral content item collection. At block  404 , the example method  400  can rank a plurality of ephemeral content item collections, including the ephemeral content item collection, based on a machine learning model. At block  406 , the example method  400  can provide at least one of the ranked plurality of ephemeral content item collections in an ephemeral content feed of a user. Other suitable techniques that incorporate various features and embodiments of the present disclosure are possible. 
       FIG. 5  illustrates an example second method  500  for ranking ephemeral content item collections, according to an embodiment of the present disclosure. It should be understood that there can be additional, fewer, or alternative steps performed in similar or alternative orders, or in parallel, based on the various features and embodiments discussed herein unless otherwise stated. Certain steps of the method  500  may be performed in combination with the example method  400  explained above. 
     At block  502 , the example method  500  can train a machine learning model based on features relating to one or more of: ephemeral content item collection attributes, ephemeral content item attributes, or user attributes. At block  504 , the example method  500  can predict a likelihood of a user engaging with an ephemeral content item collection based on the machine learning model. Other suitable techniques that incorporate various features and embodiments of the present disclosure are possible. 
     It is contemplated that there can be many other uses, applications, features, possibilities, and/or variations associated with various embodiments of the present disclosure. For example, users can, in some cases, choose whether or not to opt-in to utilize the disclosed technology. The disclosed technology can, for instance, also ensure that various privacy settings, preferences, and configurations 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 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 device having computer functionality, such as a smart-phone, a tablet, a personal digital assistant (PDA), a mobile telephone, 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. 
     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 an ephemeral content ranking module  646 . The ephemeral content ranking module  646  can be implemented with the ephemeral content ranking module  102 , as discussed in more detail herein. In some embodiments, one or more functionalities of the ephemeral content ranking module  646  can be implemented in the user device  610 . 
     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.