Not to belabor the point, but this post from a while back which discusses crowdsourcing gets it right:
Your crowdsourcing operation needs to make sure that everyone who participates (and perhaps also, people who do not) profits from the efforts of the crowd. You can make money hand-over-fist, and the crowd won’t mind – and will even cheerfully assist – so long as they are satisfied with the benefits of their participation – that means you have to understand what those benefits are, and provide for them.
Viewing a crowdsourced project as merely a parasitic path to free labor will doom it to failure. The benefits have to flow both ways. That’s the trick.
(It will be interesting to see what happens with Second Life; after getting some huge press and some impressive numbers, it seems that it is usually a ghost town. I found this to be the case when I signed up. I went in a few times and just wondered… now what? Hopefully it will continue to evolve into something more powerful and useful/interesting.)