Using PlanetAll in 1998, Amazon has convinced USPTO that it invented the "Social Networking System", with a description which sounds like good old BBS, used in the dial up days;
'A networked computer system provides various services for assisting users in locating, and establishing contact relationships with, other users. For example, in one embodiment, users can identify other users based on their affiliations with particular schools or other organizations. The system also provides a mechanism for a user to selectively establish contact relationships or connections with other users, and to grant permissions for such other users to view personal information of the user. The system may also include features for enabling users to identify contacts of their respective contacts. In addition, the system may automatically notify users of personal information updates made by their respective contacts.'You can socially engage in a discussion about this patent, prior arts associated and what facebook is going to do at Good old Slashdot!