CrowdFlower Launches Open Data Project

This is interesting, but a few concerns are nagging me:

1) There's been some research about the demographics of crowdworkers [1] that questions whether it's a representative sample of any particular population, and I wouldn't immediately concede that conclusions drawn from these survey results are externally valid.

2) There's at least a little controversy around how well (or rather, poorly) crowdworkers are paid and treated, with workers on Amazon's Mechanical Turk going as far as crowdsourcing a set of guidelines for academic requesters to right some pretty egregious wrongs that have happened in the past few years (disclosure: I was involved in the research [2] that facilitated those guidelines).

I wouldn't necessarily forsake this data or anything learned from it, but these concerns make me wary to use it myself very readily.

Does anyone else have concerns? Am I just being hyper-vigilant because this is a personal research interest? I'm open to accusations that I'm biased, at least in this case :P

[1]: Ross, Joel, et al. "Who are the crowdworkers?: shifting demographics in mechanical turk." CHI'10 extended abstracts on Human factors in computing systems. ACM, 2010.

[2]: publication/citation forthcoming; for now, a link is easier -> https://ali-alkhatib.com/media/papers/pn2032-paper.pdf