Yeah I had a go at it for a while, it's true some people are actually making a good living from jobs in SL - property, entertainment, creating game enhancements.
It's an amazing idea (although the whole thing makes me wonder what's wrong with these people's 'Real Life' that they feel they're better off most of the time in SL), but I just found it all rather dull - the interface was nasty and I couldn't figure out what to actually go and do without spending money.
Worth an hour of faffing. If you really have nothing better to do.