Warning: Philosophy ahead.
OK - you were warned. There's an article up over on the New York Times about new 3D chat rooms with avatars, etc. WoW is explicitly mentioned in the article. But of course, in an online chat room there's no game.
But there are avatars. And a virtual world.
How many of the rules of the game have to be set down by the developers before it's a 'massive game' instead of a 'virtual world' or whatever the term of the month is? Because if the answer is nearly zero, these chat rooms, like Second Life, will qualify.
That said, I've never thought second life was a game. Or at least not a fun one. It has crafting. It has player housing. In fact, if they could open up some kind of facebook API it could even have minigames.
And let's be fair: why do you keep going back to your massive game of choice? Is it for the PvE? Maybe sometimes, but I honestly think the split is more often on the side of the social aspects of massive games. So what happens if you start with social, rather than with game? At what point does it become a MMORPG from the other side? Everyone is role playing in an online environment. The only question is the word 'game'.