17. The method of claim 15 , wherein the response probability is based at least in part on a historical response rate of the user to requests for information presented by the social networking system.
15. 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 and a set of unknown information items not associated with data; obtaining a plurality of prompts associated with one or more information items from the set of unknown information items; determining, for each of the plurality of prompts associated with the one or more information items from the set of unknown 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 unknown information items in the set of unknown information items, the data acquisition value of an unknown information item based at least in part on a value to the social networking system of associating data with the unknown information item and the determined response probability; selecting an unknown information item from the set of unknown 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 selected unknown information item for presentation to the user based at least in part on the response probabilities of one or more prompts associated with the selected unknown information item.