A recent study details the way in which the Chinese on-line game market is developing and provides a few very interesting numbers regarding money spent on games. The Chinese market is best defined as an atypical one, very similar to nearby markets like those in South Korea or Japan.
The Western business model for MMOs, which implies an initial boxed buy and then paying a fixed subscription fee, is not well suited to the Eastern markets. The dominant on-line games there are usually free to play in their simplest forms and require money for micro transactions that offer the player better objects or game advantages. Giant MMO World of Warcraft recently referred to this business model as being unfair to players, as it doesn't keep the playing field level for everyone.