Unearthing just how much the game industry pulls in can be a difficult task, thanks to vagaries beyond new game sales at retail outlets. For example, the industry stat-tracking NPD Group initially stated in January that new software at US retailers amounted to some $10.5 billion of the industry's $19.66 billion haul in 2009. However, by June, NPD had revised that figure upward to $15 billion, after factoring in other forms of revenue such as used games and subscriptions.

　　World of Warcraft's subscription model appears to be slowing growth in the West. This week, Strategy Analytics has provided a look at one of the grayer areas of industry performance, that dealing with global massively multiplayer online role-playing game sales. According to the market research firm's latest report, titled "The World of MMORPG: a Tale of Two Regions," MMORPG revenues topped $5 billion worldwide in 2009, up 17 percent from a year prior.

　　Notably, the MMORPG markets in the East and West are not growing at the same rate. Strategy Analytics found that while Eastern markets have flourished since 2007, under the leadership of Shanda, Netease, Nexon, and NCsoft, Western growth, led by Blizzard Entertainment, has seen a marked slowdown.

　　"Faced with fierce competition from social games and console video games, MMORPG in the Western market has already shown signs of a slowdown," said Strategy Analytics director Martin Olausson. "The traditional subscription model that most Western MMORPGs adopt has lost traction and growth momentum." Conversely, the analytics firm noted that free-to-play, microtransaction-based models have fueled Asia's growth.

　　Despite the uneven growth, Strategy Analytics foresees a substantial rise in total MMORPG revenue in 2010. According to the firm's figures, online game sales should hit $8 billion this year.