Here is 2009's company-reported user growth of several top virtual worlds and MMOs I've been tracking: Second Life, of course, the largest user-created 3D social world; World of Warcraft, the largest Western MMO; Habbo, the biggest web-based social world, and YoVille, which is also based on the web, but played within Facebook and MySpace. As you can see, in 2009 both WoW and SL grew their userbase of unique monthlies only slightly; Habbo by contrast grew strongly, and as I suggested in 2008, eclipsed World of Warcraft. Driven by social network virality, YoVille grew far fastest of all. (And that 20 million only counts its Facebook userbase!)
The pattern to these data points? In my opinion, this:
Web-based, 2.5D worlds rule, while client-installed, 3D worlds are struggling to maintain their existing user base, or grow a new one. At least in the West, I believe this statement is generally true throughout the industry, and can't think of any obvious exceptions. Sony's Free Realms, for example, is a 3D and client-installed virtual world/MMO, and after launching last year with an impressive number of registered users, seems to have lost traction. (According to Google Trends, after falling behind for just a few months in 2009, Habbo now attracts far more unique users than Free Realms.)
Question is (if you assume my take is correct), what if anything do you think will reverse this trend, and does it matter?