It's games library contains all the big releases, MMOs, F2Ps, DOTAs and a lot of 'classic' titles - but it's woefully poor when it comes to Indie stuff. Even those super-popular Indie games, the ones which sell a tonne in every Steam Sale/Bundle, are missing in many cases (in fact more than half the games I launched in the 3-4 days I had it went unrecognised).
I can add games to my own local DB (as well as submitting them) but it won't 'track' them until they accept the submission which defeats the point of me doing it somewhat (esp as they clearly don't intend to do much work accepting submissions).
I didn't really get far beyond that tbh - if I'm going to have to hack-in half my games and not have them tracked, there's little point in me using it.
That said, Raptr aren't a lot better at the 'adding new games' thing. It boggles my mind tbh, surely the trick is to support every possible game (allowing users to add their own, even)??