Abstract: Systems and methods for social networking, in which a user of a social networking system may interact with other users, comprises using a processor to associate a telephone number, such as a cell phone number, with the user and to use the telephone number as an identifier of the user in the social networking system. A prospective contact may be identified with the telephone number of the prospective contact. The user may integrate access to multiple social networking systems by selecting one or more of the multiple networking systems as desired networking systems for the user's interaction with a contact. A contact may choose which of the multiple systems to select for interacting with the user. Further, contacts may be grouped in the networking system, and the user may present customized user profiles to contacts based on the groupings.