There are others, depending in part on your definition of success. Playfish & Playdom, for example. Non-game success stories are less common (afaik) but there a

There are others, depending in part on your definition of success. Playfish & Playdom, for example. Non-game success stories are less common (afaik) but there are still some rising stars there, too - biggest example I can think of off-hand is RootMusic.