OM goes off on commercial social networking ventures: The answer to his original question is, of course, is "the logic of collective action." Everyone building their Rolodex on their own is both redundant and deflecting of growth. Cleint/server architectures offer a way for information to be entered once and only once (as with those distributed address book things.) The companies building server-based socuial networking sites are doing so in part because doing it on a server is efficient, and in part because it is also a good way to capture value, for (they hope) later rent extraction. The trick Om wants to pull off, and its the trick of all decentralized applications, is to reconstruct the logic of collective action so that users can create value for themselves, without having their data held hostage. Napster did it by brokering connections while holding none of the user's actual music (though they never got to the "Now how do we make money?" stage) -- I wonder if a "broker intros only/connections live with the user" app could take off?