Detecting carriers for mobile devices

1. A method comprising, by a computing device:

receiving a request for a multimedia object from a mobile-client system of a first user, wherein the request comprises http-header information of the mobile-client system;

determining one or more attributes of the mobile-client system based at least on a social-graph information associated with the first user and the http-header information, wherein determining the one or more attributes comprises calculating a probability score the mobile-client system has the one or more attributes by comparing the social-graph information associated with the first user and the http-header information with a database of a social-networking system; and

sending the multimedia object to the mobile-client system in response to the request, the multimedia object being customized based on at least the determined one or more attributes of the mobile-client system.

2. The method of claim 1 , wherein the http-header information comprises at least a user-agent string describing one or more attributes of the mobile-client system.

3. The method of claim 1 , wherein the http-header information comprises at least a user-agent string describing one or more attributes of a browser client of the mobile-client system.

4. The method of claim 1 , wherein the multimedia object comprises an advertisement that is customized based on at least the determined one or more attributes of the mobile-client system.

5. The method of claim 1 , wherein the one or more attributes of the mobile-client system comprise one or more of programming language support, style-sheet language support, screen size, screen pixel density, keyboard type, location-services support, wireless communication support, image support, or video support.

6. The method of claim 1 , further comprising determining a carrier based on the determined one or more of the attributes of the mobile-client system.

7. The method of claim 6 , wherein the multimedia object is further customized based on the determined carrier.

8. The method of claim 7 , wherein customizing the multimedia object based on at least the determined carrier comprises including content associated with the carrier in the multimedia object.

9. The method of claim 7 , wherein customizing the multimedia object based on at least the determined carrier comprises including advertisements associated with the carrier in the multimedia object.

10. The method of claim 1 , further comprising determining a connection-type, and wherein the multimedia object is further customized based on the determined connection-type.

11. The method of claim 1 , further comprising determining a connection-status, and wherein the multimedia object is further customized based on the determined connection-status.

12. The method of claim 1 , further comprising determining a latency-period, and wherein the multimedia object is further customized based on the determined latency-period.

13. The method of claim 1 , further comprising:

accessing a social graph of the online social network, the social graph comprising a plurality of nodes and a plurality of edges connecting the nodes, each of the edges between two of the nodes representing a single degree of separation between them, the nodes comprising:

a first node corresponding to the first user, the first user being associated with the online social network; and

a plurality of second nodes corresponding to a plurality of second users associated with the online social network, respectively;

wherein determining the one or more attributes is further based on user information associated with the first user.

14. The method of claim 13 , wherein the user information comprises a user profile of the online social network corresponding to the first user.

15. The method of claim 14 , wherein the user information comprises information describing one or more friends of the first user corresponding to one or more second nodes, respectively, and wherein one or more friends of the first user have mobile-client systems with one or more carriers, respectively.

16. The method of claim 1 , wherein determining one or more attributes of the mobile-client system is further based on a browsing history associated with the first user.

17. The method of claim 1 , wherein determining one or more attributes of the mobile-client system comprises:

calculating a score for each attribute based on the http-header information and the social-graph information associated with the first user; and

identifying each attribute having a score greater than a threshold score.

18. The method of claim 17 , wherein the score is calculated using a machine-learned scoring formula.

19. One or more computer-readable non-transitory storage media embodying software that is operable when executed to:

receive a request for a multimedia object from a mobile-client system of a first user, wherein the request comprises http-header information of the mobile-client system;

determine one or more attributes of the mobile-client system based at least on a social-graph information associated with the first user and the http-header information, wherein determining the one or more attributes comprises calculating a probability score the mobile-client system has the one or more attributes by comparing the social-graph information associated with the first user and the http-header information with a database of a social-networking system; and

send the multimedia object to the mobile-client system in response to the request, the multimedia object being customized based on at least the determined one or more attributes of the mobile-client system.

20. A system comprising: one or more processors; and a memory coupled to the processors comprising instructions executable by the processors, the processors operable when executing the instructions to:

receive a request for a multimedia object from a mobile-client system of a first user, wherein the request comprises http-header information of the mobile-client system;

determine one or more attributes of the mobile-client system based at least on a social-graph information associated with the first user and the http-header information, wherein determining the one or more attributes comprises calculating a probability score the mobile-client system has the one or more attributes by comparing the social-graph information associated with the first user and the http-header information with a database of a social-networking system; and

send the multimedia object to the mobile-client system in response to the request, the multimedia object being customized based on at least the determined one or more attributes of the mobile-client system.