Of course, no mention of Blizzard would be complete without WoW these days. However, the game's dominance of the MMO genre means that, as the folks at Terra Nova noticed, no discussion of MMOs is really complete without WoW:
For better or worse, WoW is the face of the massive genre. In a very small part of the galaxy, it's a gravity well bending light that passes anywhere near it. When discussing PvP, questing, guilds or class balance, commentators now have a lingua franca: the common tongue of World of Warcraft.
When on the hunt for a MMO to play that isn't "just another WoW clone", then, bear in mind that many people are looking at what clearly works for inspiration. We will certainly see games with strange and innovative MMO gameplay, but will they attract the numbers necessary to survive?