My current game, Lord of the Rings Online, is going Free to Play. So is EverQuest II. Meanwhile, the casual game sector has sprouted some virtual-worldy features. The intense grindfest games shrink in significance; huge MMOGs have 90% solo content; asynchronous-distant play is the norm; don't grind, rather, buy virtual goods for real money so you can move forward at your desired pace.
In 2006 we learned from Ducheneaut, Yee, Nickell, and Moore that surprisingly few people play WoW socially. This paper, it turns out, was the first to identify online gaming's future.
One gets the impression that today, a large number of players dip into environments, sample their experiences, then move on. No subscriptions, no raids, no guilds, no groups even. No Ventrilo; only the occasional banter in general chat. No need to specialize the character or the gear. The columns of Richard Aihoshi at MMORPG.com give interesting insights into this mode of play and the business models that benefit from it.
What should we call a platform that caters to alone-togetherness? How about a Massively Single Player Online Game, or MSPOG. You can find a post on the word at FredCavazza.net. It might be a fascinating post, too; I just don't speak French well enough to know.