Unlike SI's relatively full-featured Facebook fantasy game, though, Yahoo's integration is actually pretty shallow. While Yahoo users will be able to push updates about their team to their Facebook wall and "like" specific teams with the click of a button, they won't be able to control their team from their Facebook page, or find potential opponents through their Facebook network of friends. In short, this is about sharing your Yahoo Sports activity with Facebook, rather than conducting your Yahoo Sports activity through Facebook.
Even though Yahoo doesn't yet seem ready to fully merge its proprietary fantasy football program with Facebook, it obviously sees the network's potential as a way to spread the word about the game. And when even outside social games are using your network to market their own efforts, you know you're in a dominant position.