Gigaom reports DFC Intelligence, a company specializing in market research and consulting in the video game industry, will soon reveal a “comprehensive study of massively multiplayer online worlds” next month. One of the nuggets in that study will be a list of the major MMOs and how much revenue each of them generated. To whet our number-crunching appetites, DFC has released guesstimations on what those numbers will look like (apparently all of the earnings from 2008 are still being counted).

Firmly planting itself at number one, Blizzard’s “World of Warcraft” is estimated to have generated over $500 million. With the company itself pulling in around $1.2 billion in 2007, I expect “WoW” alone to pull in almost a billion in 2008, especially considering the MMO reached 11 million subscribers in late October.

At an estimated $150 - $500 million in revenue, the title for second place is divided between the free-to-play titles “Fantasy Westward Journey,” “MapleStory,” and “Shanda,” as well as the subscription-based “Lineage I” and “Lineage 2.”

As usual, take these numbers with a grain (or perhaps a cup) of salt until the official ones are released in the coming months.