I spend 2 evenings a week raiding, with 1-2 hours throughout the week (plus another hour or two on the weekends, when I can) doing other things. Twice a week, a group of 10 friends get together, log onto WoW and a Ventrilo server, and mess around for a few hours. I think of it a lot like a bowling/poker night for some guys, except you're significantly more likely to invite a new, potentially interesting person to a WoW raid than you are to your weekly game.
Honestly, I find the whole "If it does not have direct monetary value, or somehow advance my career/list of contacts, it isn't worth doing" stance that many people take rather disturbing. No, playing WoW doesn't directly benefit me, but the indirect benefits have been pretty awesome. I've kept in touch with several old friends I otherwise wouldn't have, met a lot of interesting people, and it gives me something I can talk about with at least 10% of the population. And that's all on top of just playing a well designed, pretty fun game.