[krapp]

The only problem I can see with this is any site popular enough to need regular moderators could probably get away with offering moderation for free to their members, just for the cachet of being mods. Most of the rest of the possible cases (small personal blogs and forums, which may cost nothing or almost nothing for their owners) probably wouldn't be willing or able to afford the fees, or want to give privileges to some random person on the internet. Professional sites like online newspapers and businesses will want to farm it off on an intern or someone in house.

It seems to me that it would certainly be a difficult thing to make money at but if you can establish a reputation then it could potentially work. Although then in a few years everyone will be complaining about how this service is crushing free speech across the internet.