Lots of people have tried this. It's very hard, especially on Facebook, because people are there to spend time on Facebook first and foremost. The one excepti

Lots of people have tried this. It's very hard, especially on Facebook, because people are there to spend time on Facebook first and foremost. The one exception to this might be Zynga, but of course they're far and away the #1 app developer and I'm sure some non-trivial percentage of Facebook users come back to the site just to play Farmville.