In an upcoming "comprehensive study" by DFC Intelligence, they take a look at the top money-makers in the MMO space worldwide. To no one's surprise, World of Warcaft has topped the list, followed by several Asian MMOs like MapleStory, Lineage I and II, Shanda and Fantasy Westward Journey. As for the most users, this study doesn't touch on that. With such a wide discrepancy between active subscribers and prepaid game card users, it's a difficult number to tack down.
What makes this list frustrating is the complete lack of details involved. While WoW is reported to have earned $500 million+ in 2008, the next four on the list are reporting $150-$500 million, and the final five are reporting anything in the $50-$150 million range. To the company's credit, this isn't the final analysis. Their detailed February 16th report promises to give more information on each of the top 10 games