For the first time, the massively multiplayer online gaming (MMOG) market broke the $1 billion mark in the West in 2006, driven by subscriptions, according to a new Screen Digest report (via Next Generation).

North American MMOG subscriptions were $576 million last year, while Europe's were $299 million.

The report cited World of Warcraft as "by far the most popular subscription game," accounting for a staggering 54 percent of the subscription market in 2006. The game generated revenues of $471 million last year in the West. Jagex's Runescape was the nearest competitor.

Outside of subscriptions, the remainder of the 2006 Western MMO revenue was composed of other revenue streams such as virtual item sales and in-game ads.

Screen Digest estimates over 10 million subscription accounts will generate $1.5 billion in consumer spending by 2011. "Germany will remain the largest subscription market in Europe, followed by the U.K.," the report adds.