Pages, which companies and public figures set up to promote themselves publicly on Facebook, will become more dynamic by focusing on interactions from their "fans," in a similar way in which interactions between members and their friends take center stage in personal profiles.

Meanwhile, the personal profiles are now changing so that they can be made more broadly available, more public like Pages, allowing members to share potentially with all 175 million Facebook members, not just with their friends or others in their geographic or school networks.

This is an interesting evolution for Facebook, which for years stressed its very granular privacy options as a source of differentiation from other social-networking sites with less strict access controls. It is, however, a move by Facebook to catch up with the latest Twitter craze, which has made it clear that there is a sizable market for people who want to broadcast inane updates on their lives to anyone who cares to read them.