Yesterday, WoW Insider linked to this very interesting article over at The Daedalus Project about the life cycle of an MMO player. Here's their summary:
It's quite interesting... I can see this progression applied to just about any hobby or obsession, really. With my most recent hobby, which had kept me occupied for a few years now, I was falling into the Burnout stage. That's one of the reasons I started playing WoW in the first place. It's fun to be in the Practice stage of a hobby again.