It’s a new demographic that will bring changes.
 Right now, Facebook allows people some control over what information they reveal to various levels of “friends.” Level one is probably ex-dorm buddies and girlfriends, level two might include sales contacts and fantasy-league teammates, and level three is likely to be anyone who signs off on performance reviews.
 Visitors find they can build social capital with little effort, maybe just by sending a birthday greeting.
 One employer uses Facebook to reach people he can’t otherwise find.
 On the Web: facebook.com