4 Facebook apps to watch - Business Center - PC World

Although it got its start by enabling people to throw virtual pies at each other and turn themselves into vampires and werewolves, the Facebook ecosystem is growing up before our very eyes.

Last week, at Facebook's old offices in downtown Palo Alto, investors, media and bloggers saw what innovative startups have been building this summer on top of the Facebook platform, the main piece of technology that allows developers to program applications that work in tandem with the social network. These apps, sites and services signal a departure from the things that have typified the Facebook platform's early iteration.

These are a lot more than just games...