Yeah, I think that a lot of companies would be happy with 250K players. If you take WOW out of the equation, a couple hundred thousand players would be a very populous MMO. I'm pretty sure that CoH doesn't have that many players (had it ever?) but it's still chugging along and making tidy money by all accounts. You have to define successful I guess. If you have ~150K players, they're loyal, they enjoy the game, you can keep adding features and still turn a decent profit I think that would be a very successful MMO.