Joi Ito has been playing World of Warcraft for a while now. It's interesting to read his experiences if you would like to know more about the dynamics of such a game, and also to understand a bit more about the interaction between the real and virtual world. From both a social and a psychological perspective... He keeps on blogging his adventures, it's worth a read. And not because it's just a fun game... Joi also started a Second Life, "a home for retired Warcraft players", which is also my favorite virtual (but not unreal) world.
"It was my first raid so most of my energy was spent figuring out exactly what the hell I was supposed to be doing, but the whole mission was organized in a somewhat dysfunctional military way with teams and squad leaders. I have no idea whether I was running with a bunch of 13 year olds or professional soldiers (the game has many of both) but the raid channel chat was a bit noisy. What was disturbing was the hateful and some of the over-the-top role playing. Other members of the raid were clearly disturbed as well. I imagined a bunch of leaderless young soldiers raping and pillaging some village. I felt a bit dirty afterwards."