Bloggers get paid per review by advertisers and one of the nice things about this system is that you're not required to write positive reviews. Advertisers pay to get reviewed, if you don't like the advertiser's product you'll be allowed to explain why it sucks and still get paid.
I've subscribed a few hours ago and I haven't received any offers from advertisers yet, but fortunately ReviewMe gives you the opportunity to write a review about their own service.
How much you earn per review depends on your site's popularity. Currently it costs advertisers about $500 to get a paid review on popular blogs and $30 or less to order one on less popular blogs. Unfortunately ReviewMe takes a pretty big cut, you only get half of what the advertisers pay to ReviewMe. In my opinion a 50 percent cut is too high, 20-30 percent would be more reasonable. Currently it's much more interesting for savvy advertisers to contact me directly and offer me money to write a review. To get reviewed by me an advertiser needs to pay ReviewMe $100, of which I only get $50. For advertisers it would be cheaper to contact me directly to write a review for lets say $75. In that case I get $25 more and the advertiser saves $25.
I also have some doubts about ReviewMe's ranking system which determines how much you get paid per review. How it works isn't fully explained on their site but it looks like they use three metrics: your Alexa ranking, an estimated number of RSS subscribers to your RSS feed and your Technorati ranking.
This isn't really a good way to guess how much traffic a site gets. Like most people know Alexa data isn't a good way to guess how much traffic a site gets, just like "estimated RSS subscribers" doesn't really tell a lot. Technorati rank is also a bad way to measure how much traffic a site gets, more backlinks don't always mean a site has more traffic.
Overall I feel there's still some work on the ranking system, the current metrics aren't a perfect way to determine how many dollars a site deserves for each review it publishes. Maybe ReviewMe should consider to drop the fixed price and allow advertisers to bid how much they want to pay for each sponsored review.
When I look at ReviewMe from an advertisers perspective there's also another thing I don't really like. The current review guidelines are really really low. The only requirement is that all reviews should be at least 200 words and that it must be clear that the post is disclosed as being sponsored in some fashion. Currently it doesn't even require bloggers to provide a link to the product or service they are reviewing, which is surely something most advertisers would expect. There's also no requirement to keep the review online after it has been approved. If I would use ReviewMe to buy reviews and noticed the blog I paid $250 already removed the review from their site 3 days later I would be pretty pissed.
Overall I think ReviewMe is a nice initiative but the company still needs to do some work to improve their service. You probably won't get rich with this service but it's a nice way to make some extra income. Another positive thing are the quick payouts, ReviewMe promises to pay you on the fourth of each month by check or PayPal.