I haven't heard of them before, but they certainly look legit. $10 is rock-bottom for user testing compensation, but then again, it's better than a lot of "jobs" you can do from home over the Internet. When I did user testing as part of my job at a public University, I think we compensated our students about $15 for an hour of their time, and that was piddling compared to what most companies paid. It's actually a harder "job" than it sounds because most people find it difficult to keep up a running commentary about what they're doing while they're doing it, especially if they know they're being recorded.
I also wanted to state that, as someone who has been trained in the field of usability testing, there is actually a HUGE difference between what you will get out of random numbers like Google analytics and from usability testing as this site appears to offer. Or at least there can be, assuming the person running the study sets it up well. But even if the users are just talking as they navigate your site, you will nearly always learn useful things about not only what they are doing, but WHY and HOW they are doing it.
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