Reminds me of a chart that
Joystiq posted this summer.
This may be out of date, though. I think I heard the guys on one of 1up.com's podcasts (Legendary Thread or 1up yours, I imagine) mention that Runescape is #2 now.
What I want to point out is ToonTown's position on the chart. That's a Disney-branded mmog & it doesn't seem to be gobbling up market share. This gives me 2 seperate (and possibly contridictory) thoughts.
A) This analyst seriously overestimates the market for a kid-centric online game. Maybe kids don't want to play them, maybe their parents are (rightfully) cautious, but they just aren't playing online right now.
B) Of course, this could likely change if a
true branded kid-centric mmog showed up. I'm no expert, but based on the ToonTown commercials I saw when I TiVo'd a few old Teen Titans episodes, it's an original IP--no traditional Disney characters. If Disney or Nickelodeon dropped a mmog starring their core characters (like what Marvel & DC are doing), we might see those companies bring the "tween" demographic into the mmo fold.
EDIT: linked the wrong image.