That's right; advertising. That's why I try to update the game every know and then to make sure people don't think I died or something. I have to admit that I'm kind of bad at it though. I'm a hard worker when it comes to game development, but at a cost.
One of the best ways a creator can do IMO is to release the games on multiple portals and platforms. What it really comes down to usually is the visuals and presentation.
It's hard to please everyone though, so I try to keep a particular target audience in mind when making games.
EDIT: I understand your comment now. Thanks for elaborating.