This video, which talks about Second Life, provides a pretty good explanation of what it is. I’m still at a loss, however, as to why this is attractive to anyone. Maybe I a “virtualist,” but I think real life (first life?) is really excellent and I can’t imagine the need for a pretend one, especially one that costs money and time, and involves playacting with poorly rendered disembodied people on a computer screen.
That said, there’s something to be understood and examined here: the success of this sort of thing either means that I’m missing something about the joys of virtual worlds, or the virtualoids are missing out on the pleasures of the flesh.