Yes, my boys have been initiated into the World of Warcraft phenomenon. Nearly every morning, I come downstairs to find Xavier playing (apparently he's a Level 49, which means he's good.) Wolfie has several IRL friends who also play, so they get together online and go on quests and stuff. Sometimes one of them, I'll call him Dr. Evil, would come over and sit on the computer in the livingroom playing with Wolfie, who is on the computer in the diningroom. (Not quite as sad as Klaus and his friend sitting not five feet away from each other and talking over AIM.)
Yes, there's lot of fighting, but it's a good game, increasingly difficult/ stimulating, and cooperative, in that you need to recruit other players (actual other people!) to help you achieve most of your quests. With the new expansion pack there's an even larger world to explore. No, I don't play. I couldn't care less about virtual worlds. I'm Stan's mom in the South Park episode Make Love, Not Warcraft. "Stan's about to be killed online!" his dad yells and mom replies, "So?"
[By the way, that episode of South Park is quite awesome, but the best part was that Xavier was online playing WoW while watching the episode--which makes fun of the gamers--and he wasn't the only one. Ironic, no?]
We've had a couple incidents where we've had to restrict access to this game but for the most part, they're allowed to play as much as they want outside of school hours, so long as turns are shared equitably and they get some exercise during the day. So they play a lot. An irritating amount, actually. And I'm quite sure they don't realize just how much time they're spending online, hence World of Time Suck.
There are some who would insist they're addicted to this game. Bollocks. Yes, they spend an awful lot of time doing it. Yes, it's the first thing they think of to do when they're bored. But they're not addicted. I've not seen one incidence of shakes, obsessive thoughts or any other signs of addiction. If anything they suffer from a lack of good ideas on how to spend their time.
Eventually they'll move on to something else. Wolfie has already expressed interest in something called Age of Mythology, which promises to teach him something about mythology in addition to strategy and killing dwarves.