Of course, as the recent story of Stephen Gillett shows, many of the things we learn in WoW carry on into the real world. Leadership and dealing with people are two of the most transferable skills around, and WoW also teaches many things from multitasking to hand-eye co-ordination. However, after putting in hours of work, a few skills seem to pale in comparison to the physical rewards other hobbies produce -- a work of art is something people can relate to, even if they didn't create it themselves, whereas "level 60" or "rank 14" mean very little outside of a specific circle.
The circle, however, is widening. As MMOs like WoW become more and more popular, more people will understand the lure of achievement in a digital dimension. Have you had trouble convincing people your hobby is worthwhile and important? Or have you found a killer argument to win sceptics over?
[Thanks to Mike for the suggestion.]