19. A method comprising: presenting a plurality of prompts requesting information items associated with data describing characteristics of a user of a social networking system including a processor; logging, in a database maintained by the social networking system, a plurality of responses from the user to the plurality of prompts; maintaining a profile for the user in a user profile database maintained by the social networking system, the profile including one or more information items associated with data describing characteristics of the user identifying one or more information items from the that have not been updated within a threshold amount of time from a current time from the maintained profile; obtaining a plurality of prompts associated with the one or more identified information items; determining, for each of the plurality of prompts associated with the one or more identified information items from the identified information items, a response probability based at least in part on one or a combination of a format and content of the prompt, the response probability indicating a likelihood of the social networking system receiving a response to a prompt when presented; determining a data acquisition value for each of a plurality of the identified information items, the data acquisition value of an identified information item based at least in part on a value to the social networking system of associating data with the identified information item and the determined response probability; selecting a particular information item from the one or more identified information items by the social networking system based at least in part on the data acquisition values; and selecting, by the social networking system, a prompt associated with the particular identified information item for presentation to the user based at least in part on the response probabilities of one or more prompts associated with the particular identified information item.
19. A method comprising: presenting a plurality of prompts requesting information items associated with data describing characteristics of a user of a social networking system including a processor; logging, in a database maintained by the social networking system, a plurality of responses from the user to the plurality of prompts; maintaining a profile for the user in a user profile database maintained by the social networking system, the profile including one or more information items associated with data describing characteristics of the user identifying one or more information items from the that have not been updated within a threshold amount of time from a current time from the maintained profile; obtaining a plurality of prompts associated with the one or more identified information items; determining, for each of the plurality of prompts associated with the one or more identified information items from the identified information items, a response probability based at least in part on one or a combination of a format and content of the prompt, the response probability indicating a likelihood of the social networking system receiving a response to a prompt when presented; determining a data acquisition value for each of a plurality of the identified information items, the data acquisition value of an identified information item based at least in part on a value to the social networking system of associating data with the identified information item and the determined response probability; selecting a particular information item from the one or more identified information items by the social networking system based at least in part on the data acquisition values; and selecting, by the social networking system, a prompt associated with the particular identified information item for presentation to the user based at least in part on the response probabilities of one or more prompts associated with the particular identified information item. 24. The method of claim 19 , wherein the response probability is based at least in part on a response to a previously presented prompt received from the user.