Just seen ur post, hence the late reply.
I think a lot of them are former or current submitters. But I think you would probably have to be a good contributor and by that I mean, never to have caused any kind of stir in a forum, which probably counts out most of us who post on msg.

I did see an ad recently for microstock reviewer positions based in Australia, I have no idea what company it was though, as the ad was through an agency. I wrote a blog on the ad. as it just made me laugh, as it just seemed that anyone who likes photography could get the job. The link is below.
The ad is offline now, but I replaced the link on the blog with a jpg image of the ad.

http://www.microstockposts.com/become-a-microstock-image-reviewer/

Quote from: RacePhoto on April 25, 2011, 16:39

That and so many people are using the same Avatar that it looked like one of the regulars asking a casual question. transl8 hasn't been back in 20 days, might be awhile before the responses get read.
I was going to suggest a lobotomy might help, then some strong whiskey?

I've already been LOBOtomised; but if I must, I'll have whisky, if you don't mind.