13. A system comprising: a memory storing computer-executable instructions; and at least one processor, connected with the memory, that executes the computer-readable instructions to perform a method that comprises: accessing information sources for data related to a user of a social network; determining that profile information is missing for classification of the user on the social network; computing, based on the determining that the profile information is missing, candidate expertise summaries for the user based on the information sources and an inferred classification of the user generated from an evaluation of: popularity of the user including communications posted by the user, re-communications by other users of the communications posted by the user and mentions of the user by the other users in the social network; selecting an expertise summary of the user from the candidate expertise summaries; and presenting the expertise summary for viewing by other users of the social network.
13. A system comprising: a memory storing computer-executable instructions; and at least one processor, connected with the memory, that executes the computer-readable instructions to perform a method that comprises: accessing information sources for data related to a user of a social network; determining that profile information is missing for classification of the user on the social network; computing, based on the determining that the profile information is missing, candidate expertise summaries for the user based on the information sources and an inferred classification of the user generated from an evaluation of: popularity of the user including communications posted by the user, re-communications by other users of the communications posted by the user and mentions of the user by the other users in the social network; selecting an expertise summary of the user from the candidate expertise summaries; and presenting the expertise summary for viewing by other users of the social network. 16. The system of claim 13 , wherein the method, executed by the at least one processor, further comprises selecting the expertise summary from the candidate expertise summaries based on quality assessment criteria.