Patent Publication Number: US-10771932-B1

Title: Device actions based on device power

Description:
PRIORITY 
     This application is a continuation under U.S.C. § 120 of U.S. patent application Ser. No. 14/619,918, filed on 11 Feb. 2015, which is a continuation under U.S.C. § 120 of U.S. Pat. No. 8,989,818, filed on 17 Aug. 2012, which is a continuation-in-part under U.S.C. § 120 of U.S. Pat. No. 8,954,100, filed on 4 Nov. 2011. 
    
    
     TECHNICAL FIELD 
     This disclosure generally relates to data communication. 
     BACKGROUND 
     When two computing devices are connected to a network, data may be transmitted between the two devices over the network using one or more suitable network protocols. A network can be the Internet, a corporate intranet, a virtual private network, a local area network, a wireless local area network, a cellular network, a wide area network, a metropolitan area network, or a combination of two or more such networks. 
     A social networking system, such as a social networking website, enables its users to interact with it and with each other through the system. The social networking system may create and store a record, often referred to as a user profile, in connection with the a user. The user profile may include a user&#39;s demographic information, communication channel information, and personal interests. The social networking system may also create and store a record of a user&#39;s relationships with other users in the social networking system (e.g., social graph), as well as provide services (e.g., wall-posts, photo-sharing, event organization, messaging, games, or advertisements) to facilitate social interaction between users in the social networking system. The social networking system may transmit contents and messages related to its services to a user&#39;s client device over a network. 
     SUMMARY OF PARTICULAR EMBODIMENTS 
     In one embodiment, factors or operating conditions related to the energy consumption of a mobile device are determined locally at the mobile device. These factors or conditions may include the device&#39;s battery level, the activity level of a user of the device, the signal strength at the device, or the time of day. A pre-determined device state that corresponds to these factors or operating conditions is identified. For example, the device state may be a napping mode (where notifications are pushed to the device from a server every few minutes), a sleep mode (where notifications are only sent when a user requests them), or a trickle mode (where notifications are pushed in real-time). Based on this pre-determined device state, an action related to energy consumption by the mobile device is taken. For example, the brightness of the display of the mobile device may be changed, a vibration mode of the mobile device may be enabled or disabled, or a volume level may be adjusted. The mobile device may wake from the napping or sleep modes in some embodiments only for notifications or messages of a certain type or from a certain source. Additionally, the user of the mobile device may customize settings related to the pre-determined device states. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example network environment. 
         FIG. 2  illustrates an example method of managing message transmission from a server to a mobile device based on the mobile device&#39;s user interface mode. 
         FIG. 3  illustrates examples of user interface modes, device operating modes, and notification modes. 
         FIG. 3A  illustrates example radio connection states. 
         FIG. 3B  illustrates an example method for determining a device action based on a device operating condition. 
         FIG. 4  illustrates an example method of managing message transmission from a server to a mobile device. 
         FIG. 4A  illustrates an example method of transmitting a message queue. 
         FIG. 4B  illustrates another example method of transmitting a message queue. 
         FIG. 5  illustrates an example block diagram for computing a measure of affinity for users in a social networking system. 
         FIG. 6  illustrates an example social networking environment. 
         FIG. 7  illustrates an example method for computing a measure of affinity for a user based on a request. 
         FIG. 8  illustrates an example computer system. 
         FIG. 9  illustrates an example mobile device platform. 
     
    
    
     DESCRIPTION OF EXAMPLE EMBODIMENTS 
     A social network, in general, is a social structure made up of entities, such as individuals or organizations, that are connected by one or more types of interdependency or relationships, such as friendship, kinship, common interest, financial exchange, dislike, or relationships of beliefs, knowledge, or prestige. A social-networking system may create and store a record in connection with a user and may also create and store a record of a user&#39;s relationships with other users in the social-networking system (e.g., in the form of a social graph). Some social-networking systems exist on the Internet in the form of social-networking websites. Such social-networking websites enable their members, who are commonly referred to as website users, to perform various social activities. For example, the social-networking website enables its users to communicate with their friends via emails, instant messages, or blog postings, organize social events, share photos, receive news of their friends or interesting events, play games, organize events, etc. 
     In particular embodiments, entities of a social network (including, for example, individuals, organizations, locations, or events) may have associated web pages within a social-networking website. Each of these web pages may contain information related to its associated entity. For example, a web page for a user of the social-networking system or website, which may be referred to as a user profile page, may contain information about the user including, for example photographs of the user, information about the user&#39;s interests, or the user&#39;s academic or professional background. Similarly, the profile page for an event, a location, or an organization may contain information about the event (e.g., invitees, time, and place of the event), the location (e.g., pictures of the location or a map of the location), or the organization (e.g., information about the organization and its members or the contact information of the organization). The profile page for a user or other entity may be accessible to other users or entities of the social-networking system depending, for example, on privacy settings for the profile page. For example, the social-networking system may allow users to post information or messages (such as, for example, user status, comments, photographs, or multimedia files) known as “posts” on another user or entity&#39;s profile page in a section of the page known as a “wall.” In particular embodiments, the wall of a profile page of an entity may be a pre-determined section of a profile page that is accessible to other entities of the social network. In particular embodiments, the wall of a profile page may be organized in a dynamically arranged, chronological manner, and this type of wall may be referred to as a “timeline” for an entity of the social network. The social networking system may transmit contents and messages related to its services to a user&#39;s client device over a network. 
     In data communication, a server may transmit one or more messages to a client device over a computer network. For example, a server system running email exchange software may transmit via the Internet email messages to a user&#39;s client device (e.g., a desktop computer, a mobile phone, or a tablet computer). The user can access the email messages received at the client device by using an email program running on the mobile device. 
       FIG. 1  illustrates an example network environment in which one or more messages may be transmitted from a server to a mobile device. In particular embodiments, server  120  may communicate with mobile device  122  and transmit one or more messages to mobile device  122  through network cloud  121 . Server  120  may comprise one or more computers or computing devices. In particular embodiments, server  120  may be operably connected to one or more message services  112 . Each message service  112  can be one or more computers or computing devices configured to transfer messages to one or more users. For example and without limitation, a message can be an email, an instant message (IM), a Short Message Service (SMS) message, a Multimedia Messaging Service (MIMS) message, a news item, an advertisement, a system update message, or any combinations of those. For example, a message can be a notification indicating a request to establish a real-time communication session (e.g., a phone call or a video call). For example, server  120  may access message services  112  for one or more outgoing messages for a user, and transmit the one or more outgoing messages to the user&#39;s mobile device  122  via network cloud  121 . 
     Network cloud  121  generally represents a network or collection of networks (such as the Internet, a corporate intranet, a virtual private network, a local area network, a wireless local area network, a cellular network, a wide area network, a metropolitan area network, or a combination of two or more such networks) over which server  120  may communicate with mobile device  122 . 
     Mobile device  122  is generally a portable computer or computing device including functionality for communicating (e.g., remotely) over a network. For example, mobile device  122  can be a mobile phone, a tablet computer, a laptop computer, a handheld game console, an electronic book reader, or any other suitable portable device. Mobile device  122  may execute one or more client applications, such as a web browser or a special-purpose client application, to access and view content and messages transmitted from server  120  over network cloud  121 . In particular embodiments, mobile device  122  may connect to network cloud  121  via a base station  131  of a cellular network (e.g., a Global System for Mobile Communications or GSM cellular network or a Long Term Evolution or LTE network). In particular embodiments, mobile device  122  may connect to network cloud  121  via a wireless access point  132  of a WI-FI network. 
     A mobile device (e.g., a mobile phone, a tablet computer) often runs solely on its battery. Meanwhile, receiving messages over a wireless network can decrease (e.g., by the mobile device&#39;s wireless transceiver unit) a substantial amount of energy stored in the mobile device&#39;s battery. With an abundance of messages (such as described above) available for a user to consume at the user&#39;s mobile device, it is desirable to manage message transmission to the user&#39;s mobile device in order to conserve the mobile device&#39;s battery power. Particular embodiments herein describe methods of managing transmitting messages to a user&#39;s mobile device. More specifically, particular embodiments manage transmitting messages to a user&#39;s mobile device based on the user&#39;s interaction with the mobile device. For example, particular embodiments can transmit one or more messages in real-time to a user&#39;s mobile device if the user is actively interacting with the mobile device (e.g., the user is accessing one or more applications running on the mobile device). For example, particular embodiments can transmit one or more messages to the user&#39;s mobile device only as the user requests, if the user is not actively interacting with the mobile device while the mobile device is not near the user (e.g., the user may be asleep). 
     A mobile device may have one or more operating conditions associated with it. These operating conditions may include, for example and without limitation, user interface modes and device operating modes, and the operating conditions may relate to energy consumption of the mobile device. In particular embodiments, these operating conditions may be dynamic or changing, e.g., with the energy consumption of the mobile device.  FIG. 2  illustrates an example method of managing message transmission from a server to a mobile device based on the mobile device&#39;s user interface mode. The example method of  FIG. 2  can be implemented by a mode manager process running on one or more processors of a mobile device of a user. For example, the mobile device can be a mobile phone, a tablet computer, a laptop computer, a handheld game console, an electronic book reader, or any other suitable portable device. In particular embodiments, server  120  may communicate and transmit messages to the mobile device via network cloud  121  (e.g., the Internet), as illustrated in  FIG. 1 . In particular embodiments, the mobile device may connect to network cloud  121  via a base station  131  of a cellular network and/or an access point  132  of a WI-FI network, as illustrated in  FIG. 1 . In particular embodiments, the mode manager process may determine a notification mode based on the mobile device&#39;s user interface mode ( 201 ). A notification mode may be a state of the mobile device and may, in particular embodiments, be a pre-determined state of the mobile device. In particular embodiments, the mode manager process may transmit to one or more computing devices (e.g., server  120 ) a message comprising the notification mode, causing the one or more computing devices to transmit one or more messages to the mobile device based on the notification mode ( 202 ). 
       FIG. 3  illustrates examples of user interface modes, device operating modes, and notification modes for the example method of  FIG. 2 . In particular embodiments, the mode manager process may determine a trickle notification mode based on a current user interface mode indicating that the user is actively interacting with the mobile device. As an example, the mode manager process may determine that the user is actively interacting with the mobile device if the user is touching a touch-sensitive portion of the mobile device including, for example, a touch screen or a touch pad. As another example, the mode manager process may determine that the user is actively interacting with the mobile device if the user is interacting with one or more applications running on the mobile device. The mode manager process may determine whether the user is interacting with a particular application by determining whether the particular application&#39;s user interface receives user input or receives user interface focus within a pre-determined time duration (e.g., within the last 20 seconds). For example, the mode manager process can determine whether the particular application&#39;s user interface receives user input (or receives user interface focus) within a pre-determined time duration by accessing the mobile device&#39;s operating system or subscribing as a listener to user input events of the particular application. 
     For example, the mode manager process may determine whether the user is interacting with a message reader application running on the mobile device. For example, the mode manager process may determine whether the user is interacting with an application other than a message reader on the mobile device. A message reader can be a special-purpose client application. A message reader can also be a web browser displaying one or more structured documents (e.g., a web page, an iFrame) for accessing one or more messages (e.g., email web interface or social networking web user interface). In particular embodiments, the mode manager process may determine a trickle notification mode ( 310 ) if the current user interface mode is that the user is interacting with a message reader application running on the mobile device ( 301 ) or that the user is interacting with an application other than a message reader on the mobile device ( 302 ), as illustrated in  FIG. 3 . In particular embodiments, the mode manager process may transmit to server  120  a message indicating the trickle notification mode, causing server  120  to transmit one or more messages to the mobile device in real-time. For example, in response to the message indicating the trickle notification mode, a server-side process running on server  120  can access one or more message services  112  for one or more outgoing message for the user, and transmit the one or more outgoing messages to the user in real-time (e.g., whenever a new outgoing message is available). 
     In particular embodiments, the mode manager process may determine a napping notification mode based on a current user interface mode indicating that the user is not actively interacting with the mobile device while the mobile device is near the user—e.g., the mobile device can be in the user&#39;s pocket while the user walks or drives a car. The mode manager process may determine that the user is not interacting with the mobile device if no application running on the mobile device receives user input (e.g., a user touch on a touch-sensitive portion of the mobile device) or user input focus within a pre-determined time duration (e.g., within the last 3 minutes). In other embodiments, the mode manager process may determine that the user is not interacting with the mobile device if the mobile device&#39;s display is in a lower-power or lower-usage state (e.g., the display is powered down, or a screen saver or a screen lock program is active). The mode manager can determine that the mobile device is near the user if the mobile device is in motion (e.g., indicating that the user is carrying the mobile device). The mode manager process can determine whether the mobile device is in motion by accessing a device driver of an accelerometer of the mobile device. 
     In particular embodiments, the mode manager process may determine a napping notification mode ( 311 ) if the user is not interacting with the mobile device while the mobile device is in motion ( 303 ), as illustrated in  FIG. 3 . In particular embodiments, the mode manager process may transmit to server  120  a message indicating the napping notification mode, causing server  120  to transmit one or more messages to the mobile device at a pre-determined time interval (e.g., every 10 minutes). For example, in response to the message indicating the napping notification mode, a server-side process running on server  120  can access one or more message services  112  for one or more outgoing messages for the user, and transmit the one or more outgoing messages to the mobile device every 10 minutes. 
     In particular embodiments, the mode manager process may determine a sleep notification mode based on a current user interface mode indicating that the user is not actively interacting with the mobile device while the mobile device is stationary for a pre-determined time duration (e.g., the mobile device is stationary for the last 15 minutes). For example, the user may be asleep. As described earlier, the mode manager process can determine that the user is not interacting with the mobile device if no application running on the mobile device receives user input (e.g., a user touch on a touch-sensitive portion of the mobile device) or user input focus within a pre-determined time duration. The mode manager process can also determine that the user is not interacting with the mobile device if the mobile device&#39;s display is in a lower-power or lower-usage state. The mode manager process can determine whether the mobile device is stationary or idle by accessing a device driver of an accelerometer of the mobile device. 
     In particular embodiments, the mode manager process may determine a sleep notification mode ( 312 ) if the user is not interacting with the mobile device while the mobile device is stationary ( 304 ), as illustrated in  FIG. 3 . In particular embodiments, the mode manager process may transmit to server  120  a message indicating the sleep notification mode, causing server  120  to transmit one or more messages to the mobile device as the user requests. That is, server  120  does not transmit messages to the mobile device unless the user requests to access messages. For example, the user may access a message reader application (described earlier), causing the mode manager process to transmit to server  120  a message indicating a trickle notification mode ( 310 ), as described earlier. In response to the message indicating the trickle notification mode, a server-side process running on server  120  can access one or more message services  112  for one or more outgoing message for the user, and transmit the one or more outgoing messages to the user. 
     The mode manager process may determine notification modes based on different combinations of user interface modes, device operating modes, or any other type of operating conditions of the mobile device including, for example, any sensory input data available to the mobile device. The mode manager process may determine operating conditions or notification modes in real time, and may determine them locally at the mobile device. Additionally, the notification modes of the mobile device may be dynamic or changing. For example, the mode manager process may determine a napping notification mode if the user is interacting with an application other than a message reader application on the mobile device ( 302 ), or if the user is not interacting with the mobile device while the mobile device is in motion ( 303 ). The mode manager process may determine a trickle notification mode if the user is interacting with a message reader application running on the mobile device ( 301 ), if the user is interacting with any other application on the mobile device ( 302 ), or if the device has a high battery level or a strong cellular signal. The mode manager process may determine a sleep notification mode if the user is not interacting with the mobile device while the mobile device is stationary ( 304 ) or in motion ( 303 ). 
     Furthermore, the mode manager process may determine a notification mode based on the mobile device&#39;s device operating mode, including, for example, the device&#39;s power state. For example, the mode manager process can access a device driver for the mobile device&#39;s battery and determine that the battery level is low (e.g., less than 20% charged). In order to conserve battery energy, mode manager process may determine a sleep notification mode ( 312 ) if the battery level is low ( 305 ), as illustrated in  FIG. 3 . In other embodiments, the mode manager process may determine a napping notification mode or a trickle notification mode if the battery level is high (e.g., greater than 90% charged). As another example, the mode manager process may determine a trickle notification mode if the battery is being charged. The mode manager process may also determine a notification mode based on a combination of user interface modes or device operating modes. For example, the mode manager process may determine a trickle notification mode if the battery level is high, even if the user is not interacting with the mobile device while the mobile device is in motion ( 303 ). 
     The mode manager process may also determine a notification mode based on the mobile device&#39;s current radio network state, another example of a device operating mode of the mobile device. For example, the mode manager process can access a device driver of the mobile device&#39;s wireless communication subsystem and determine a signal strength of the current radio network connection (e.g., 4 out of 5 bars). For example, a radio network connection with a weak signal strength (e.g., 1 out of 5 bars) may not be efficient (thus consuming more energy) in data communication due to packet loss. The mode manager process may determine a sleep notification mode ( 312 ) if the current radio network connection&#39;s signal strength is low ( 306 ), as illustrated in  FIG. 3 . The mode manager process may determine a trickle notification mode ( 310 ) if the current radio network connection&#39;s signal strength is high (e.g., 4 out of 5 bars). Additionally, in other embodiments, the mode manager process may access a device driver of the mobile device&#39;s wireless communication subsystem, determine a type of radio network for the current radio network connection (e.g., GSM or LTE), and determine a notification mode based on the type of radio network. For example, a GSM-type radio network connection may consume less energy than an LTE-type radio network connection, so the mode manager process may determine a trickle notification mode ( 310 ) if the type of radio network is GSM and a napping notification mode ( 311 ) if the type of radio network is LTE. The mode manager process may also determine a notification mode based on a combination of user interface modes or device operating modes. For example, the mode manager process may determine a trickle notification mode ( 310 ) if the type of radio network is LTE and the battery level (or cellular signal) is high, or the mode manager process may determine a napping notification mode ( 311 ) if the type of radio network is GSM and the battery level (or cellular signal) is low. As another example, the mode manager process may determine a sleep notification mode if the user is not interacting with the mobile device while the mobile device is in motion ( 303 ) and either the battery is low ( 305 ) or the cellular signal is weak ( 306 ). 
     The mode manager process may also determine a notification mode based on sensor data available to the mobile device, another example of a device operating mode of the mobile device. As an example, sensor data may be gathered from one or more sensors of sensor subsystems  918  at the mobile device. These sensors may include, by way of example and without limitation, light sensors (e.g., to determine ambient light levels), proximity sensors (e.g., to determine the presence of nearby objects), gyroscopes (e.g., to determine orientation), accelerometers (e.g., to determine speed or acceleration), altimeters (e.g., to determine altitude positioning), motion sensors (e.g., to determine motion), temperature sensors (e.g., to measure ambient temperature), biometric sensors (e.g., for fingerprint reading), or GPS sensors (e.g., for location positioning). For example, if the mobile device is determined based on accelerometer measurements to be traveling at 60 miles per hour and also, based on GPS sensor measurements, to be traveling along a highway route, the mode manager process may determine a napping notification mode ( 311 ), as a user of the mobile device may likely be driving. As another example, if the ambient light level is low and the GPS sensor measurements indicate that the mobile device is located at the home of a user of the mobile device, the mode manager process may determine a sleep notification mode ( 312 ), as a user of the mobile device may likely be sleeping. The mode manager process may also determine a notification mode based on a combination of user interface modes or device operating modes (e.g., determined from sensor data). 
     The mode manager process may also determine a notification mode based on the time of day (e.g., at the location of the mobile device), another example of a device operating mode of the mobile device. For example, if the time of day is between midnight and 5 a.m., the mode manager process may determine a sleep notification mode ( 312 ), as a user of the mobile device may likely be asleep. As another example, if the time of day is between 10 p.m. and midnight, the mode manager process may determine a napping notification mode ( 311 ), as a user of the mobile device may not be sleeping but may not be checking his or her mobile device as frequently. The mode manager process may also determine a notification mode based on a combination of user interface modes or device operating modes. As another example, if the time of day is between midnight and 5 a.m. and the battery level is high, the mode manager process may determine a napping notification mode ( 311 ). 
     Particular embodiments may further change the mobile device&#39;s radio network state based on a notification mode. For didactic purposes,  FIG. 3A  illustrates Radio Resource Control (RRC) connection modes for GSM and evolved UMTS (Universal Mobile Telecommunication System) Terrestrial Radio Access Network (E-UTRAN) cellular network connections. This disclosure contemplates any combination of radio network states of any type of cellular network. In the example of  FIG. 3A , after power-on, a mobile device stays in IDLE state ( 350 ) until the mobile device establishes a connection with a base station by transitioning to DCH (Dedicated Channel) connected mode ( 351 ) or FACH (Forward Access Channel) connected mode ( 353 ). In addition to DCH connected mode and FACH connected mode, the mobile device can also connect to the base station in PCH (Paging Channel) connected mode ( 352 ). Among the connected modes, DCH connected mode can have the highest data bandwidth and highest energy consumption (e.g., 2 MB/sec, 200 mA). FACH connected mode has lower data bandwidth but consumes about 50% of the energy of DCH connected mode (e.g., 4 kB/sec, 100 mA). PCH connected mode has zero data bandwidth but consumes about 1-2% of the energy of DCH connected mode (e.g., no data, 2 mA). The mobile device can transition from a higher power and data bandwidth connected state to a lower power and data bandwidth connected state (e.g.,  360 ,  361 , and  362  of  FIG. 3A ) to conserve energy consumption while remaining in connection with a base station. Transitions  360 ,  361 , and  362  can be triggered by using a timer. For example, the base station may transition the radio connection with the mobile device from a higher power and data bandwidth connected state to a lower power and data bandwidth connected state 10 seconds after the mobile device completes a data transfer session. The mobile device can also actively transfer the radio connection with the base station from a higher power and data bandwidth connected state to a lower power and data bandwidth connected state, without waiting for the timer to expire, by sending to the base station a request for transitioning to a lower power and bandwidth connected state (e.g., a fast dormancy request described in CR3483R2 in 3GPP TS 25.331 Release 8). 
     In particular embodiments, the mode manager process may determine a second radio network state based on the notification mode. In particular embodiments, the mode manager process may transmit to a cellular base station a request for the second radio network state, causing the base station to transition a connection between the mobile device and the cellular base station to the second radio network state. For example, the mode manager process may determine a sleep notification mode ( 312 ) based on a user interface mode ( 304 ), as illustrated in  FIG. 3 . Since during a sleep notification mode, server  120  does not send messages to the mobile device unless the user requests, it is desirable to have a lower power and data bandwidth mode to conserve the mobile device&#39;s battery life. For example, the mode manager process can transmit to base station  131  a request for IDLE connected mode, causing base station  131  to transition the radio connection between the mobile device and base station  131  to IDLE connected mode ( 322 ). Similarly, for example, the mode manager process may determine a napping notification mode ( 311 ) based on a user interface mode ( 303 ), as illustrated in  FIG. 3 . The mode manager process can transmit to base station  131  a request for PCH connected mode, causing base station  131  to transition the radio connection between the mobile device and base station  131  to PCH connected mode ( 321 ). As yet another example, the mode manager process may determine a trickle notification mode ( 310 ) based on a user interface mode ( 301  or  302 ), as illustrated in  FIG. 3 . The mode manager process can transmit to base station  131  a request for FACH connected mode, causing base station  131  to transition the radio connection between the mobile device and base station  131  to FACH connected mode ( 320 ). 
     In particular embodiments, the mode manager process may determine an action for the mobile device to take based on the device&#39;s operating conditions including operating mode, notification mode, or any combination of the two. As an example, the mode manager process may determine to change a brightness of a display of the mobile device (e.g., lower the brightness to lower energy consumption) if, for example, the battery level is low or if the device is in a napping notification mode. The mode manager process may determine to change a threshold idle time before turning off the display of the mobile device (e.g., increase the threshold idle time) if, for example, the battery level is high or if the device is in a trickle notification mode. The mode manager process may determine to enable or disable a vibrator of the mobile device. For example, if the device is in a trickle notification mode and the battery level is low, the vibrator may be disabled (to lower energy consumption by the vibrator), but if the device is in a napping notification mode and the battery level is high, the vibrator may be enabled. Similarly, the mode manager process may determine to change a volume level of the mobile device to decrease or allow more energy consumption by the mobile device. For example, if the device is in a trickle notification mode and the battery level is low, the volume level may be lowered. The mode manager process may determine to enable or disable one or more sounds of the mobile device. For example, if the battery level is low, certain ringtones (e.g., entire clips of songs that consume larger amounts of energy) may be disabled. In particular embodiments, the action for the mobile device to take may include waking the mobile device from a sleep or napping notification mode, entering a trickle notification mode, or changing from one notification mode to another, generally. 
       FIG. 3B  illustrates an example method for determining a mobile device action based on the device&#39;s operating mode, notification mode, or any other operating condition of the device (e.g., associated with the device&#39;s energy consumption). The method may begin at step  315 , where one or more operating conditions of the mobile device (e.g., related to energy consumption by the mobile device) are determined (e.g., in real time or locally at the mobile device). At step  325 , a pre-determined device state (e.g., a notification mode) that corresponds to the operating conditions of the mobile device is identified. At step  335 , an action for the mobile device to take is determined, based at least in part on the pre-determined device state, and the action may be related to energy consumption by the mobile device. Particular embodiments may repeat one or more steps of the method of  FIG. 3B , where appropriate. Although this disclosure describes and illustrates particular steps of the method of  FIG. 3B  as occurring in a particular order, this disclosure contemplates any suitable steps of the method of  FIG. 3B  occurring in any suitable order. Moreover, although this disclosure describes and illustrates particular components, devices, or systems carrying out particular steps of the method of  FIG. 3B , this disclosure contemplates any suitable combination of any suitable components, devices, or systems carrying out any suitable steps of the method of  FIG. 3B . 
     In particular embodiments, a user of the mobile device may customize what types of notification modes are entered or what types of actions are taken at the mobile device. The user may customize what types and what levels of operating conditions (e.g., user interface modes or device operating modes) lead the mobile device to enter a particular notification mode or take a particular actions. As an example, a user may set a custom preference that any time the battery level is at or below 60% of the full battery charge, the mobile device enters a napping notification mode. As another example, a user may set a custom preference that if the user is not interacting with the mobile device while the mobile device is in motion (e.g., in the user&#39;s pocket), the display of the mobile device is turned off after three seconds (e.g., to save energy consumption). User customization may occur via settings on the mobile device itself (e.g., via a mobile device interface) or via settings on a server of a social-networking website (e.g., via a browser interface). 
     As described earlier, particular embodiments may determine a notification mode for a mobile device based on the mobile device&#39;s user interface mode, device operating mode, or any combination of these modes. Particular embodiments may transmit to a server a message indicating the notification mode, causing the server to transmit messages to the mobile device based on the notification mode. For example, the server can transmit messages to the mobile device in real-time based on if the notification mode is a trickle notification mode. For example, the server can transmit messages to the mobile device every 10 minutes if the notification mode is a napping notification mode. In addition to transmitting outgoing messages to the mobile device based on the notification mode, particular embodiments may transmit outgoing messages to the mobile device further based on a ranking of the outgoing messages, as illustrated in  FIG. 4 . 
     In particular embodiments, server  120  may receive from the user&#39;s mobile device a message comprising a notification mode (e.g., a trickle notification mode or a napping notification mode) of the mobile device ( 401 ). In particular embodiments, server  120  may receive from the user&#39;s mobile device a message comprising the mobile device&#39;s user interface mode, health, or operating mode, such as the battery life, time of day, signal strength, wireless network availability (WiFi or 3G/4G), whether or not the device is charging, etc., and server  120  may determine a notification mode for the mobile device. In particular embodiments, the mobile device may transmit the factors that determine the notification mode of the mobile device, for example variables  301 - 306 , to server  120 . In particular embodiments, server  120  determines the notification mode of the mobile device, and transmits an instruction to the mobile device to adjust its notification mode. In particular embodiments, the mobile device determines its own notification mode but still transmits information (e.g., a flag) regarding its notification mode, system health, or user interface mode to server  120 . 
     The message may further comprise an identifier (e.g., a user name, a phone number, an email address) of the user. In response to the message, a server-side process running on server  120  may access one or more message services  112  indicating one or more outgoing messages for the user ( 402 ). The server-side process may access one or more message services  112  for information for the one or more outgoing messages. For example, information for an outgoing message may comprise one or more identifiers (e.g., a user name, a phone number, an email address) of the outgoing message&#39;s originator. 
     In particular embodiments, the server-side process may determine a value for each of the one or more outgoing messages ( 403 ). In particular embodiments, the server-side process may determine a value for each of the one or more outgoing messages based on the content of each of the one or more outgoing messages. For example, the server-side process may assign a higher value to a message having content indicating urgency (e.g., the words “urgent,” “important,” or “emergency”). In particular embodiments, the server-side process may determine a value for each of the one or more outgoing messages based on a location of the mobile device (e.g., determined from a GPS sensor on the mobile device) or other sensor data of the mobile device. For example, if the server-side process receives location information from the mobile device (e.g., GPS coordinates) indicating the mobile device is near a restaurant where the friend of a user of the mobile device is currently located (e.g., checked in), an outgoing message indicating the location of the friend may be assigned a higher value (due to the user&#39;s proximity to the restaurant and friend) than it might otherwise be assigned. As described further below, this higher value may allow the outgoing message indicating the location of the friend to be delivered to the mobile device (due to the user&#39;s proximity to the restaurant and friend) when it might otherwise have not been immediately delivered. In particular embodiments, the server-side process may determine a value for each of the one or more outgoing messages based on an affinity or social relevancy between each of the one or more outgoing messages and the user—i.e., based on an affinity between each outgoing message&#39;s originator and the user. Outgoing messages such as notifications of posts in specific groups relevant to the user, replies to the user&#39;s own posts, or replies to the user&#39;s own comments on a post may all be scored using affinity. For example, the server-side process may assign each of the one or more outgoing messages an affinity score. For example, the server-side process can assign an affinity score of 1.0 to an outgoing message if the outgoing message&#39;s originator is the user&#39;s immediate family member (e.g., parent, sibling), or an affinity score of 0.9 if the outgoing message&#39;s originator frequently communicates with the user, or an affinity score of 0.7 if the outgoing message&#39;s originator is the user&#39;s first-degree social contact in a social graph of a social networking system. Interaction between users on a social networking system, such as chats, wall posts, emails, and the like, can also be used in scoring affinities between users of the social networking system. Methods of measuring affinity scoring are described later. 
     Particular embodiments may transmit more outgoing messages to the mobile device if the user is interacting with the mobile device, while transmitting fewer outgoing messages to the mobile device if the user is not actively interacting with the mobile device. In particular embodiments, the server-side process may transmit at least one outgoing message to the mobile device based on the notification mode and respective values of the one or more outgoing messages ( 404 ). For example, in response to a message from the mobile device indicating a trickle notification mode (e.g., the user is interacting with the mobile device), the server-side process can select outgoing messages with affinity scores greater than a pre-determined threshold (e.g.,  0 . 4 ), and transmit the selected outgoing messages to the mobile device. In contrast, for example, in response to a message from the mobile device indicating a napping notification mode (e.g., the user is not interacting with the mobile device while the mobile device is in motion), the server-side process can select only high-affinity outgoing messages (e.g., messages most relevant to the user) by using a higher threshold (e.g.,  0 . 8 ), and then transmit the selected high-affinity outgoing messages to the mobile device. In particular embodiments, the mobile device may only be responsive (e.g., may only wake up from a napping or sleep notification mode) to messages of a certain type or messages from a certain source. This may be managed by the mode manager process running on the mobile device. In particular embodiments, this may be accomplished via the setting of pre-determined thresholds for affinity scores (e.g., either by the server-side process or by the mobile device and communicated to the server-side process). For example, if the mobile device will only wake up from a sleep or napping notification mode for a message from an immediate family member or for a message with content indicating urgency, the pre-determined threshold for transmitting an outgoing message to the mobile device (and waking the mobile device) may be 1.0, which may be a high affinity score. 
     In addition to transmitting to the mobile device outgoing messages with the highest affinity scores, particular embodiments may store one or more remaining outgoing messages in a queue and transmit them to the mobile device at a later time. In particular embodiments, the server-side process may select and store in a queue one or more of the one or more outgoing messages based on respective values of the one or more outgoing messages and the notification mode. For example, the server-side process can select outgoing messages with affinity scores of less than 0.4 and store the selected message in a queue if the notification mode is a trickle notification mode. For example, the server-side process can select outgoing messages with affinity scores of less than 0.8 and store the selected messages in a queue if the notification mode is a napping notification mode. 
     The server-side process may transmit at least one of the queued outgoing messages to the mobile device at a later time. For example, the server-side process may transmit at least one queued outgoing message to the mobile device at a pre-determined time interval (e.g., every 30 minutes). For example, the server-side process may transmit at least one queued outgoing message to the mobile device when a size of the queue is greater than a pre-determined threshold (e.g., when the queue has more than 20 queued messages). For example, the server-side process may transmit at least one queued message to the mobile device when a real-time outgoing message (e.g., a phone call) is transmitted to the mobile device. For example, the server-side process may transmit at least one queued outgoing message to the mobile device when a high affinity outgoing message (e.g., a message with an affinity score greater than 0.8) is transmitted to the mobile device. That is, the server-side process can piggy-back at least one queued outgoing message with another real-time or high-affinity outgoing message. 
       FIG. 4A  illustrates an example method of queuing and transmitting messages to the mobile device based on the mobile device&#39;s reported notification mode, or alternatively, the mobile device&#39;s reported system health. At Step  405 , one or more server-side processes on server  120  may receive an outgoing message from message services  112 . As previously disclosed, the message may be any type of notification or communication to be transmitted to the mobile device, including but not limited to: instant messages, friend requests and acceptances thereof, another user writing on the wall of the user, another user tagging a photo of the user, check-ins from nearby users, status messages from the user&#39;s friends, and the like. 
     At Step  406 , the one or more server-side processes on server  120  assign a score to the outgoing message. As previously disclosed, the score may be assigned based on an affinity score. In particular embodiments, the affinity score may be a predictor of the relative degree of interest the user has in such a message. In such embodiments, a predictor function may be a machine learning algorithm based on the previous historical engagement of the user with messages of the same type. Message affinity scoring is described in greater detail with reference to  FIGS. 5 and 7 . In particular embodiments, messages may be assigned values based on a predetermined categorization of messages. For example, particular messages may be deemed more important to all users, such as instant messages, wall posts, or friend requests, whereas other messages may be of significantly less importance. In particular embodiments, messages are divided into real-time messages and non-real-time messages. This disclosure contemplates any suitable method of calculating message scores for individual outgoing messages. 
     At Step  407 , the one or more server-side processes on server  120  add the newly scored message to an outgoing message queue and add the score to a running sum of all the message scores in the message queue. Thus the total queue score is incremented by the score calculated for the particular message in Step  407 . 
     At Step  408 , the one or more server-side processes on server  120  determine whether the sum of all message scores in the outgoing message queue exceeds a predetermined threshold. The threshold may be adjusted in real-time by the one or more server-side processes based on the notification mode message, or alternatively, the indication of system health, received from the mobile device. In particular embodiments, higher power consumption notification modes may translate to a “healthier” device, and the threshold value may be decreased. For example, if the mobile device reports that it has full battery, is plugged in, and is connected to a WiFi network, the threshold may be set to zero, resulting in the server-side processes on server  120  pushing messages to the mobile device substantially in real-time. At the other extreme, if the mobile device reports that it has under 10% battery life and is on the edge of a 3G network, the one or more server-side processes on server  120  may increase the threshold to an extremely high number, for example, 100. In particular embodiments, reception of a message comprising a notification mode or mobile device status triggers an interrupt which updates the threshold and forces the process of  FIG. 4A  to jump to Step  408 . Therefore, in such embodiments, if a device reports its “health” has increased, for example, by moving from an area with only 3G access to an area having WiFi access, the server-side process on server  120  adjusts the threshold value for the mobile device downward, and performs a check to determine if the queue should be transmitted. Thus, a change in mobile device health or notification mode may trigger transmission of the queue, even in the absence of a new message. 
     If the one or more server-side processes on server  120  determine at Step  408  that the sum of the scores in the outgoing message queue exceeds the threshold value, it transmits all the messages in the outgoing message queue to the mobile device, empties the queue, and clears the sum. If the sum of the message scores in the outgoing message queue fails to exceed the threshold in Step  408 , the process returns to Step  405 , where it waits the reception of another outgoing message to the mobile device. 
       FIG. 4B  illustrates another example method of piggybacking less important message transmission with the transmission of more important messages. Like the method of  FIG. 4A , the method of  FIG. 4B  adjusts the transmission of outgoing messages based on the relative importance of an outgoing message and the notification mode or device health of the mobile device. 
     At Step  410 , one or more server-side processes on server  120  receive an outgoing message destined for a mobile device. At Step  411 , the server-side processes on server  120  calculate a timeout for the message. In particular embodiments, the timeout of a message is inversely proportional to the determined importance, and inversely related to the relative health or notification mode of the mobile device. For example, certain messages may be so important that their timeout value may be zero (that is, they are transmitted to the user immediately and substantially in real-time). For example, an instant message marked “urgent” may have a timeout value of zero. At the other extreme, an extremely low value status message from a distant friend may have an infinite timeout value; the message will never be sent on its own. In particular embodiments, the timeout value for each outgoing message may be determined by affinity scoring as described below, with the timeout inversely related to the affinity of the message. The timeout values for each individual message are also inversely related to the device health or notification mode. Thus, if the device is in a promiscuous (high message) notification mode, such as DCH mode, the timeout values for individual messages are shortened by a predetermined factor. Conversely, if the mobile device is in a low message transmission mode, or reports poor health (again, for didactic purposes, low battery life or low network connectivity), the timeout period for each message may be multiplied by a predetermined scale factor greater than 1. This disclosure contemplates any suitable method of calculating timeouts for individual outgoing messages. 
     At Step  412 , the outgoing message is stored in a message queue. In particular embodiments, the one or more server-side processes on server  120  maintain a separate timer for each of the outgoing messages in the outgoing message queue. In particular embodiments, the server-side process maintains a single system timer, and stores a countdown value and start time for each message in the outgoing message queue. This disclosure contemplates any suitable method of determining whether any individual outgoing message has timed out. 
     At Step  413 , the one or more server-side processes on server  120  determine whether any message in the outgoing message queue has timed out. In particular embodiments, the timeout of any message in the outgoing message queue triggers an interrupt process that immediately branches the method of  FIG. 4B  to Step  414 . If no messages have timed out, the process returns to Step  410 , where it awaits reception of a new message to be transmitted to the outgoing device. 
     At Step  414 , if any of the messages in the outgoing message queue times out, the one or more server-side processes in server  120  transmit all the messages in the outgoing message queue to the mobile device and empty the queue. The process then repeats itself with the reception of the next outgoing message destined for the mobile device. The aforementioned methods merely illustrate two example server-side message transmission algorithms. This disclosure contemplates other methods based on message importance, user affinity to the message, device transmission mode, or device health. As a general principle, the mobile device is aware of the resource cost of receiving a message, based on the various factors described with reference to  FIG. 3 , (battery life, user interaction, network connection, and the like), whereas the server is aware of the value of the information or message to be transmitted to the user (based on social factors and empirical engagement). After being informed of the resource cost by the mobile device, the server may base its decision on whether to transmit a message to the mobile device if the value exceeds the cost. This disclosure contemplates any suitable method of calculating, or distributing the calculation of, the resource cost associated with receiving a piece of information. This disclosure contemplates any suitable method of calculating, or distributing the calculation of, the subjective value of a piece of information to a particular user or the objective value of a piece of information to all users. 
     In one embodiment, a process running in a social networking environment requests a measure of affinity for a particular user from a module that implements an affinity function. The module, in one implementation, computes the requested measure of affinity by combining (e.g., adding) a weighted set of predictor functions, where each predictor function predicts whether the user will perform a different action. The weights may be provided by the process that requests the measure of affinity, which allows the requesting process to weight the predictor functions differently. In this sense, the affinity function is tunable by the requesting process for its own purpose. In one implementation, affinities may be computed for the purposes of computing an affinity score of an outgoing message to an intended recipient. 
     The predictor functions may predict whether a user will perform a particular action based on the user&#39;s interest in the action. For example, a predictor function may be derived based on a user&#39;s historical activity (such as interacting with other users utilizing the social networking system functionality discussed above, for example). Additionally, the predictor function may include a decay factor that causes the strength of the signal provided by the user&#39;s historical activity to decay with time. The predictor functions may predict any number of actions, which may be within or outside of the social networking system. For example, these actions may include various types of a user&#39;s communications, such as messages, posting of content, and commenting on content; various types of a user&#39;s observation actions, such as viewing profiles of other connections and viewing photos and content posted by other connections; and various types of coincidence information about two or more users, such as being tagged in the same photograph, checked in at the same location, and attending the same event. A predictor function may be determined using a machine learning algorithms trained on historical activity and past user responses or data farmed from users by exposing them to various options and measuring responses. 
     To predict the likely actions a user may take in a given situation, any process on the social networking system or outside may request a measure of affinity for a user by providing a set of weights. The measure of affinity may reflect the user&#39;s interest in other users, content, actions, advertisements, or any other objects in the social networking system. The weights may be binary or, more generally, any real number. In one implementation, messages intended for a communications device of a subject user that are transmitted or intermediated by the social networking system, for example, may be processed to compute an affinity between the subject user and the message. The affinity value can be appended to the message prior to transmission to the communications device. In other implementations, a process hosted on the communications device may access the affinity module to request the measure of affinity. In some implementations, the communications device may request affinities between the subject user of the communications device and one or more other users identified in a contacts database of the subject user (stored locally on the communications device or remotely on the social networking system). Revised affinity values can be obtained during subsequent synchronization processes. Communications device may use these affinity values for messages from the respective users. In other implementations, the communications device may monitor interactions locally and compute affinity values locally. 
       FIG. 5  is a block diagram of a function for computing a measure of affinity for users in a social networking system. To compute a measure of affinity  615  that indicates a set of likely actions a user may want to take in any given situation, weights  105  are applied to predictor functions  610  and then combined to obtain a measure of affinity  615 . Although  FIG. 5  shows three predictor functions  610 , any number of predictor functions can be employed in other embodiments. Additionally, in the embodiment of  FIG. 5 , the weighted predictor functions  610  are combined linearly. In different embodiments, other forms of combination may be used, including harmonic means, mean squares, and geometric means. Additionally, multiple measures of affinity  615  with varying weights  605  may be computed before predicting a user&#39;s actions. 
     The weights  605  of the affinity function enable it to be used by various processes in the social networking system environment for different purposes. For example, in a process that provides advertisements with social endorsements from a viewer&#39;s friends, an ad algorithm may use the measure of affinity  615  function to determine which of a user&#39;s connections to mention in the social endorsement or what type of actions to mention in the endorsement. The measure of affinity  615  may then be based on those predictor functions  610  that show how interested the user is in viewing the content posted by another user as well as one or more predictor functions  610  that show how interested the user is in various actions that may be mentioned in the social endorsement. The ad algorithm would thus provide relatively large weights for these predictor functions  610  so that the resulting measure of affinity would more accurately determine which social endorsements would be more interesting to the viewing user. The ad algorithm would then select the social endorsement using the resulting measure of affinity, thereby increasing the likelihood of conversion of the advertisement. 
     As a second example, in a process for a messaging application that intermediates communications between users, a social algorithm may use the measure of affinity  615  function to determine what level of interest a user may have in a message sent by a particular sending user. The measure of affinity  615  for this purpose may be based on predictor functions  610  that show how interested the user is in viewing the content posted by the user&#39;s connections and/or how often the users send messages to one another in general, as well as one or more predictor functions  610  that show how interested the user is posting or accessing different types of messages. Accordingly, the social algorithm would weight these predictor functions  610  relatively high so that the resulting measure of affinity would accurately determine which messages would be more interesting to the viewing user. Because of the highly tunable nature of the affinity function, enabled by the weighted predictor functions  610 , it can be used for a number of different purposes. 
       FIG. 6  is a high-level block diagram of an environment of a social networking system, according to one embodiment.  FIG. 6  illustrates a social networking system  700 , a user device  702 , and an external server  704  connected by a network  708 . The social graph  718  stores the connections that each user has with other users of the social networking system  100 . The social graph  718  may also store second-order connections, in some embodiments. The connections may thus be direct or indirect. For example, if user A is a first-order connection of user B but not of user C, and B is a first-order connection of C, then C is a second-order connection of A on the social graph  718 . 
     The action store  740  stores actions that have been performed by the users of the social networking system  700 , along with an indication of the time associated with those actions and references to any objects related to the actions. Additionally, the action store  740  may store statistics for specified categories of actions. For example, for a given user the action store  740  may contain the number of wall posts in 30 days by a user, messages sent by the user, number of photos posted by the user in 30 days and number of distinct users that received the user&#39;s comments in 30 days. For a given connection between two users, user A and user B, the action store  740  may contain actions such as the number of profile page views from A to B, the number of photo page views from A to B, the number of messages from A to B, and the number of times A and B were tagged in the same photo, and these actions may be associated with a timestamp or may be filtered by a cutoff (e.g., 24 hours, 90 days, etc.). The actions recorded in the action store  740  may be farmed actions, which are performed by a user in response to the social networking system  700  providing suggested choices of actions to the user. 
     The predictor module  720  is responsible for computing a set predictor functions  610 , which predict whether a user will perform a set of corresponding actions. As discussed above, each predictor function  610  may be representative of a user&#39;s interest in a particular action associated with the predictor function  610 . The historical activity of a user may be used as a signal of a user&#39;s future interest in the same activity. In some embodiments, the predictor function  610  is generated using a machine learned algorithm that is trained using a user&#39;s historical activity associated with an action. The predictor module  720  thus provides a predictor function  610  for each of a set of actions, where a predictor function  610  may take as an input the a user&#39;s historical activity and then outputs a measure of the likelihood that the user will engage in the corresponding activity. 
     In some embodiments, one or more of the predictor functions  610  may use a decay factor in which the strength of the signal from a user&#39;s historical activity decays with time. Moreover, different predictor functions  610  may decay the historical activity at different rates. For example, some types of user activity, like adding a new connection, indicate a more persistent interest than other types of activity that indicate a more ephemeral interest, like commenting on another user&#39;s status. Therefore, the predictor functions  610  may decay the effect of historical activity based on an understanding about how that activity may become less relevant over the passage of time. Various decay mechanisms may be used for this purpose. For example, a predictor function  610  may use a mathematical function, such as an exponential decay, to decay the statistics about a user behavior. In another embodiment, the decay is implemented by selecting only those statistics about a user behavior that occurred within a specific window of time, such as 24 hours or 30 days. 
     In one embodiment, a predictor function  610  is realized as a ratio of two affine functions as shown in equation (1). The numerator and denominator affine functions take statistics of the user&#39;s historical activity as inputs. 
     
       
         
           
             
               
                 
                   P 
                   = 
                   
                     
                       
                         a 
                         0 
                       
                       + 
                       
                         
                           a 
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                         ⁢ 
                         
                           x 
                           1 
                         
                       
                       + 
                       
                         
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                           x 
                           2 
                         
                       
                       + 
                       … 
                       + 
                       
                         
                           a 
                           n 
                         
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                           x 
                           n 
                         
                       
                     
                     
                       
                         b 
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                       + 
                       
                         
                           b 
                           1 
                         
                         ⁢ 
                         
                           x 
                           
                             n 
                             + 
                             1 
                           
                         
                       
                       + 
                       … 
                       + 
                       
                         
                           b 
                           m 
                         
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                           x 
                           
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                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     where 
     P is the predictor function  610 ; 
     a i  for i=0, 1, 2, . . . , N are the coefficients in the numerator affine function; 
     b i  for i=0, 1, 2, . . . , M are the coefficients in the denominator affine function; and 
     x i  for i=1, 2, . . . , N+M are the statistics on a user&#39;s historical activity related to the predictor function P. 
     The denominator affine function can represent a normalization of the numerator affine function. For example, the number of comments made by a user may be normalized by, among other statistics, the number of times the user has been active on the social networking system  700 . In particular, by altering b i  for i=0, 1, 2, . . . , M the normalization pattern can be changed. In some embodiments, some or all of the coefficients, a i  for i=0, 1, 2, . . . , N and b i  for i=0, 1, 2, . . . , M, are determined through machine learning, which may be implemented by the predictor module  720 . In a particular embodiment, a supervised machine learning algorithm is used with the training data obtained through farming, by providing a statistically significant number of users several options and monitoring their response. In another embodiment, the supervised machine learning algorithm is trained entirely based on historical user activity and past responses to choices of actions. The predictor functions  610  may also be non-linear. An example embodiment implements a predictor function  610  for a family where the predictor function  610  includes an ‘if-then’ construct for the members of the family—i.e., the predictor function  610  is computed differently depending on whether it is being computed for the parents or the children. 
     Some predictor functions  610  in the social networking system  700  may predict actions related to a user&#39;s communication in the social networking system  700 . The statistics specifically related to communications may include broadcast data and communication data. Broadcast data may include, for example, the number of photos posted by the user in a given time period, the number of posts via applications by the user in a given time period, and any other communication that the user has posted or otherwise distributed to a group of other users. Communication data may include, for example, the number of likes from the user in a given time period, number of comments posted by user in a given time period, and any other information about the user&#39;s communication activities. 
     Similarly, some predictor functions  610  in the social networking system  700  may predict actions related to a user&#39;s observation of content in the social networking system  700 . The statistics specifically related to observation may include, for example, the number of profile page views by the user of another user in a given time period, the number of photo views by the user in a given time period, the number of views of an advertisement containing a social endorsement in a given time period, and any other activity involving the viewing of content by the user. 
     Finally, some predictor functions  610  in the social networking system  700  may predict actions related to a user&#39;s coincidence with one or more other users of the social networking system. The statistics specifically related to coincidence may include, for example, a rate at which two or more users have been tagged in the same photograph, have checked in at the same location, or have confirmed (e.g., via RSVP) that they will be attending the same event, and any other activity involving an action or object in the social networking system related to multiple users. 
     The affinity module  760  provides a measure of affinity  615  based on input data about the user from the social networking system  700  using the predictor functions  610 . In the embodiment of  FIG. 5 , the affinity module  760  sums the predictor functions linearly as shown in equation (2). However, other implementations are equally feasible.
 
 A=β   0 +β 1   P   1 +β 1   P   2 + . . . β 5   P   S    (2)
 
     where
         A is the measure of affinity  615  requested;   P i  for i=0, 1, 2, . . . , s are the s predictor functions  610  in the social networking system  700 ; and   ß i  for i=1, 2, . . . , s are the weights  605  assigned to the s predictor functions  610  in the social networking system  100 .       

       FIG. 7  illustrates an embodiment of a method for computing a measure of affinity  615  for a user based on a request. The social networking system  700  first receives  771  a request from a process for a measure of affinity  615  for a user along with the weights  605  to be assigned to the various predictor functions  610 . The request may include the message for which an affinity score is desired or one or more attributes extracted from the message. The social networking system  700  then computes  772  the predictor functions  610  for the user in the predictor module  772 . The predictor functions  610  previously computed are combined to determine  773  an overall measure of affinity  615 , which is then provided  774  to the requesting process. 
       FIG. 8  illustrates an example computer system  800 , which may be used with some embodiments. This disclosure contemplates any suitable number of computer systems  800 . This disclosure contemplates computer system  800  taking any suitable physical form. As example and not by way of limitation, computer system  800  may be an embedded computer system, a system-on-chip (SOC), a desktop computer system, a mobile computer system, a game console, a mainframe, a mesh of computer systems, a server, or a combination of two or more of these. Where appropriate, computer system  800  may include one or more computer systems  800 ; be unitary or distributed; span multiple locations; span multiple machines; or reside in a cloud, which may include one or more cloud components in one or more networks. Where appropriate, one or more computer systems  800  may perform without substantial spatial or temporal limitation one or more steps of one or more methods described or illustrated herein. As an example and not by way of limitation, one or more computer systems  800  may perform in real time or in batch mode one or more steps of one or more methods described or illustrated herein. One or more computer systems  800  may perform at different times or at different locations one or more steps of one or more methods described or illustrated herein, where appropriate. 
     In particular embodiments, computer system  800  includes a processor  802 , memory  804 , storage  806 , an input/output (I/O) interface  808 , a communication interface  810 , and a bus  812 . In particular embodiments, processor  802  includes hardware for executing instructions, such as those making up a computer program. As an example and not by way of limitation, to execute instructions, processor  802  may retrieve (or fetch) the instructions from an internal register, an internal cache, memory  804 , or storage  806 ; decode and execute them; and then write one or more results to an internal register, an internal cache, memory  804 , or storage  806 . In particular embodiments, processor  802  may include one or more internal caches for data, instructions, or addresses. In particular embodiments, memory  804  includes main memory for storing instructions for processor  802  to execute or data for processor  802  to operate on. As an example and not by way of limitation, computer system  800  may load instructions from storage  806  to memory  804 . Processor  802  may then load the instructions from memory  804  to an internal register or internal cache. To execute the instructions, processor  802  may retrieve the instructions from the internal register or internal cache and decode them. During or after execution of the instructions, processor  802  may write one or more results (which may be intermediate or final results) to the internal register or internal cache. Processor  802  may then write one or more of those results to memory  804 . One or more memory buses (which may each include an address bus and a data bus) may couple processor  802  to memory  804 . Bus  812  may include one or more memory buses, as described below. In particular embodiments, one or more memory management units (MMUs) reside between processor  802  and memory  804  and facilitate accesses to memory  804  requested by processor  802 . In particular embodiments, memory  804  includes random access memory (RAM). This RAM may be volatile memory, where appropriate Where appropriate, this RAM may be dynamic RAM (DRAM) or static RAM (SRAM). 
     In particular embodiments, storage  806  includes mass storage for data or instructions. As an example and not by way of limitation, storage  806  may include an HDD, a floppy disk drive, flash memory, an optical disc, a magneto-optical disc, magnetic tape, or a Universal Serial Bus (USB) drive or a combination of two or more of these. Storage  806  may include removable or non-removable (or fixed) media, where appropriate. Storage  806  may be internal or external to computer system  800 , where appropriate. In particular embodiments, storage  806  is non-volatile, solid-state memory. In particular embodiments, storage  806  includes read-only memory (ROM). Where appropriate, this ROM may be mask-programmed ROM, programmable ROM (PROM), erasable PROM (EPROM), or flash memory or a combination of two or more of these. 
     In particular embodiments, I/O interface  808  includes hardware, software, or both providing one or more interfaces for communication between computer system  800  and one or more I/O devices. Computer system  800  may include one or more of these I/O devices, where appropriate. One or more of these I/O devices may enable communication between a person and computer system  800 . As an example and not by way of limitation, an I/O device may include a keyboard, microphone, display, touch screen, mouse, speaker, camera, another suitable I/O device or a combination of two or more of these. An I/O device may include one or more sensors. This disclosure contemplates any suitable I/O devices and any suitable I/O interfaces  808  for them. Where appropriate, I/O interface  808  may include one or more device or software drivers enabling processor  802  to drive one or more of these I/O devices. I/O interface  808  may include one or more I/O interfaces  808 , where appropriate. Although this disclosure describes and illustrates a particular I/O interface, this disclosure contemplates any suitable I/O interface. 
     In particular embodiments, communication interface  810  includes hardware, software, or both providing one or more interfaces for communication (such as, for example, packet-based communication) between computer system  800  and one or more other computer systems  800  or one or more networks. As an example and not by way of limitation, communication interface  810  may include a network interface controller (NIC) for communicating with an Ethernet or other wire-based network or a wireless NIC (WNIC) for communicating with a wireless network, such as a WI-FI network. This disclosure contemplates any suitable network and any suitable communication interface  810  for it. As an example and not by way of limitation, computer system  800  may communicate with an ad hoc network, a personal area network (PAN), a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), or one or more portions of the Internet or a combination of two or more of these. One or more portions of one or more of these networks may be wired or wireless. As an example, computer system  800  may communicate with a wireless PAN (WPAN) (e.g., a BLUETOOTH WPAN), a WI-FI network (e.g., a 802.11a/b/g/n WI-FI network,), a WI-MAX network, a cellular network (e.g., a Global System for Mobile Communications (GSM) network, a Long Term Evolution (LTE) network), or other suitable wireless network or a combination of two or more of these. 
     In particular embodiments, bus  812  includes hardware, software, or both coupling components of computer system  800  to each other. As an example and not by way of limitation, bus  812  may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a front-side bus (FSB), a HYPERTRANSPORT (HT) interconnect, an INFINIBAND interconnect, a low-pin-count (LPC) bus, a memory bus, a Peripheral Component Interconnect Express or PCI-Express bus, a serial advanced technology attachment (SATA) bus, a Inter-Integrated Circuit (I2C) bus, a Secure Digital (SD) memory interface, a Secure Digital Input Output (SDIO) interface, a Universal Serial Bus (USB) bus, a General Purpose Input/Output (GPIO) bus, or another suitable bus or a combination of two or more of these. Bus  812  may include one or more buses  812 , where appropriate. 
     The client-side functionality described above can be implemented as a series of instructions stored on a computer-readable storage medium that, when executed, cause a programmable processor to implement the operations described above. While the mobile device  122  may be implemented in a variety of different hardware and computing systems,  FIG. 9  shows a schematic representation of the main components of an example computing platform of a client or mobile device, according to various particular embodiments. In particular embodiments, computing platform  902  may comprise controller  904 , memory  906 , and input output subsystem  910 . In particular embodiments, controller  904  which may comprise one or more processors and/or one or more microcontrollers configured to execute instructions and to carry out operations associated with a computing platform. In various embodiments, controller  904  may be implemented as a single-chip, multiple chips and/or other electrical components including one or more integrated circuits and printed circuit boards. Controller  904  may optionally contain a cache memory unit for temporary local storage of instructions, data, or computer addresses. By way of example, using instructions retrieved from memory, controller  904  may control the reception and manipulation of input and output data between components of computing platform  902 . By way of example, controller  904  may include one or more processors or one or more controllers dedicated for certain processing tasks of computing platform  902 , for example, for 2D/3D graphics processing, image processing, or video processing. 
     Controller  904  together with a suitable operating system may operate to execute instructions in the form of computer code and produce and use data. By way of example and not by way of limitation, the operating system may be Windows-based, Mac-based, or Unix or Linux-based, or Symbian-based, among other suitable operating systems. The operating system, other computer code and/or data may be physically stored within memory  906  that is operatively coupled to controller  904 . 
     Memory  906  may encompass one or more storage media and generally provide a place to store computer code (e.g., software and/or firmware) and data that are used by computing platform  902 . By way of example, memory  906  may include various tangible computer-readable storage media including Read-Only Memory (ROM) and/or Random-Access Memory (RAM). As is well known in the art, ROM acts to transfer data and instructions uni-directionally to controller  904 , and RAM is used typically to transfer data and instructions in a bi-directional manner. Memory  906  may also include one or more fixed storage devices in the form of, by way of example, hard disk drives (HDDs), solid-state drives (SSDs), flash-memory cards (e.g., Secured Digital or SD cards), among other suitable forms of memory coupled bi-directionally to controller  904 . Information may also reside on one or more removable storage media loaded into or installed in computing platform  902  when needed. By way of example, any of a number of suitable memory cards (e.g., SD cards) may be loaded into computing platform  902  on a temporary or permanent basis. 
     Input output subsystem  910  may comprise one or more input and output devices operably connected to controller  904 . For example, input output subsystem may include keyboard, mouse, one or more buttons, and/or, display (e.g., liquid crystal display (LCD), or any other suitable display technology). Generally, input devices are configured to transfer data, commands and responses from the outside world into computing platform  902 . The display is generally configured to display a graphical user interface (GUI) that provides an easy to use visual interface between a user of the computing platform  902  and the operating system or application(s) running on the mobile device. Generally, the GUI presents programs, files and operational options with graphical images. During operation, the user may select and activate various graphical images displayed on the display in order to initiate functions and tasks associated therewith. Input output subsystem  910  may also include touch based devices such as touch pad and touch screen. A touchpad is an input device including a surface that detects touch-based inputs of users. Similarly, a touch screen is a display that detects the presence and location of user touch inputs. Input output system  910  may also include dual touch or multi-touch displays or touch pads that can identify the presence, location and movement of more than one touch inputs, such as two or three finger touches. 
     In particular embodiments, computing platform  902  may additionally comprise audio subsystem  912 , camera subsystem  912 , wireless communication subsystem  916 , sensor subsystems  918 , and/or wired communication subsystem  920 , operably connected to controller  904  to facilitate various functions of computing platform  902 . For example, Audio subsystem  912 , including a speaker, a microphone, and a codec module configured to process audio signals, can be utilized to facilitate voice-enabled functions, such as voice recognition, voice replication, digital recording, and telephony functions. For example, camera subsystem  912 , including an optical sensor (e.g., a charged coupled device (CCD), image sensor), can be utilized to facilitate camera functions, such as recording photographs and video clips. For example, wired communication subsystem  920  can include a Universal Serial Bus (USB) port for file transferring, or a Ethernet port for connection to a local area network (LAN). Additionally, computing platform  902  may be powered by power source  932 . 
     Wireless communication subsystem  916  can be designed to operate over one or more wireless networks, for example, a wireless PAN (WPAN) (e.g., a BLUETOOTH), a WI-FI network (e.g., an 802.11a/b/g/n network), a WI-MAX network, a cellular network (such as, for example, a Global System for Mobile Communications (GSM) network, a Long Term Evolution (LTE) network). Additionally, wireless communication subsystem  916  may include hosting protocols such that computing platform  902  may be configured as a base station for other wireless devices. Other input/output devices may include an accelerometer that can be used to detect the orientation of the device. 
     Sensor subsystems  918  may include one or more sensor devices to provide additional input and facilitate multiple functionalities of computing platform  902 . For example, sensor subsystems  918  may include GPS sensor for location positioning, altimeter for altitude positioning, motion sensor for determining orientation of a mobile device, light sensor for photographing function with camera subsystem  914 , temperature sensor for measuring ambient temperature, and/or biometric sensor for security application (e.g., fingerprint reader). 
     In particular embodiments, various components of computing platform  902  may be operably connected together by one or more buses (including hardware and/or software). As an example and not by way of limitation, the one or more buses may include an Accelerated Graphics Port (AGP) or other graphics bus, a front-side bus (FSB), a HYPERTRANSPORT (HT) interconnect, an Industry Standard Architecture (ISA) bus, an INFINIBAND interconnect, a low-pin-count (LPC) bus, a memory bus, a Peripheral Component Interconnect Express PCI-Express bus, a serial advanced technology attachment (SATA) bus, a Inter-Integrated Circuit (I2C) bus, a Secure Digital (SD) memory interface, a Secure Digital Input Output (SDIO) interface, a Universal Serial Bus (USB) bus, a General Purpose Input/Output (GPIO) bus, an Advanced Microcontroller Bus Architecture (AMBA) bus, or another suitable bus or a combination of two or more of these. 
     Herein, a computer-readable non-transitory storage medium or media may include one or more semiconductor-based or other integrated circuits (ICs) (such, as for example, field-programmable gate arrays (FPGAs) or application-specific ICs (ASICs)), hard disk drives (HDDs), hybrid hard drives (HHDs), optical discs, optical disc drives (ODDs), magneto-optical discs, magneto-optical drives, floppy diskettes, floppy disk drives (FDDs), magnetic tapes, solid-state drives (SSDs), RAM-drives, SECURE DIGITAL cards or drives, any other suitable computer-readable non-transitory storage media, or any suitable combination of two or more of these, where appropriate. A computer-readable non-transitory storage medium may be volatile, non-volatile, or a combination of volatile and non-volatile, where appropriate. 
     Herein, “or” is inclusive and not exclusive, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A or B” means “A, B, or both,” unless expressly indicated otherwise or indicated otherwise by context. Moreover, “and” is both joint and several, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A and B” means “A and B, jointly or severally,” unless expressly indicated otherwise or indicated otherwise by context. 
     The scope of this disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments described or illustrated herein that a person having ordinary skill in the art would comprehend. The scope of this disclosure is not limited to the example embodiments described or illustrated herein. Moreover, although this disclosure describes and illustrates respective embodiments herein as including particular components, elements, functions, operations, or steps, any of these embodiments may include any combination or permutation of any of the components, elements, functions, operations, or steps described or illustrated anywhere herein that a person having ordinary skill in the art would comprehend. Furthermore, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative.