Until the general public is willing to get past "Free" and pay for some things like a review site or an article from a blog, the companies paying the bills will be the ones deciding what kind of service the public gets.
Even if you get micropayments figured out, and people start clicking the litte $$/££ button on your site, how do you motivate someone to leave positive reviews? It's similar to being in IT, or in the tech side of stage production: if you're doing your job correctly, no one notices and they're unlikely to be motivated to comment positively.
The only method that comes to mind that solves this kind of problem is an escrow company. You hire for services via the escrow, pay them for service, they withhold payment until you are satisfied or until you don't reply, and once payment is delivered, you can no longer leave negative feedback. Written contracts managed by the escrow party would also be a must.