The problem with many a sociable game is that it's often bloody hard to find your real life friends in them. Second Life and Eve are just about okay for this: the server architecture allows everyone on at the same time (in theory) in the same place. But most games are 'sharded', or spread across multiple servers, which is horrible architectural design usually born of technical desperation and financial constraint.
Example: Stef and Kay just got WoW, and have created characters on a UK server (Alliance too, sigh) that no-one's on. Or maybe Tom's got some characters on it, but meanwhile, Jon, Dishmop, Jen, Kim and Ian are all on Runetotem. The Terranovans are all on Magtheridon, as is Brinstar (but Alliance, so we can't talk). Bunnie, Sean and Joi are all scattered elsewhere, and I'm sure there are a whole ton of friends and acquaintances and bloggers who are playing, on servers that are unaccessible to my two level 60 Crystaltipses.
To add insult to injury, Blizz have patched the Euro servers in a way that makes them incompatible with the US servers: i.e. if you have one game install, like I do, you can't switch between accounts on different servers with the same game installation any more. Blizz doesn't like it if you don't buy two copies of the game to go with your two accounts.
Rubbish, isn't it?
MySpace gets the sociable aspect: everyone can play, in the same space, but over time it's boring. WoW gets the play aspect: over time it's interesting, but not everyone can play in the same space...which is boring. I relish the day when there's a game that's so popular that everyone's playing it, and so cleverly designed that everyone can find everyone else.
That day will be a great day indeed.