A good modding community can update a game for free because they want to, unlike developers doing it because they have to, in my opinion. Still, WoW is successful so good for them.
Not only that but it's the source of so many great videos:
http://www.youtube.com/watch?v=Rwh1MWg1LLA
Music by Wierd Al - The Hardware Store.
I simply love the list of items they read off.
