The first MMO I got hooked on was EverQuest. The harsh nature of the game forced you to bond with other people. Some of those bonds have lasted longer than I played the game. I started EQ seven years ago, and while it's been at least a year since I've logged in, I still chat with people I met in-game even though they've quit as well.
Because WoW is an easier game than EQ (we can debate whether WoW is a training wheel game about as long as we can debate casual vs. hardcore), I'm concerned it might not have a long-lasting social fabric. In many ways my EQ guild was like family: we loved and fought (usually amongst ourselves) as much as most families. A guild alliance that lasted not even a year still has people stopping by to say "hi" six years after it disbanded. People stop by their old EQ guilds all the time. A lot of the time it's like old soldiers getting together to talk about a bad situation. "Say, Gan, remember that time it took us ten hours to almost clear Fear, and we wiped near the end and it and it took another ten to get our corpses? Was that a pain or what?" Shared misery can make for some long-lasting friendships.
In my EverQuest guild, I had over 2,000 posts on our guild's message boards. In my various WoW guilds I'm lucky if I have 50 over the last two years. One-third of my AIM list is people I met in EQ; zero are from WoW. How about you? How often do you talk out-of-game with other players, and will you keep in touch after you've quit the game? Is it because WoW doesn't have the hardships of other games, or am I just and old fogey remembering the good old days?