copied from lmn8r from IGN forums
"I still use XFire since it tracks things more thoroughly than Steam does, but Raptr seems like a pretty substantial competitor:
http://raptr.com/
The games list seems very complete, it has one-click joining like XFire does. It even tracks when you're playing Flash games. The one main thing I don't think it does, however, is an in-game overlay, meaning that you'd have to alt+tab to talk with people. "