Or, alternatively, should there be a few tens of thousands of firms allowed to advertise on the Internet and the rest of us can just pound sand?
(... actually, now that I think that "out loud," a distributed trust model would be an interesting idea. Google, instead of vetting ads, could vet trusted ad resellers, and knock entire resellers off the network that failed to do due diligence. The resellers would be responsible for policing their various houses and if you didn't like the terms one provided you could go to another. This is, perhaps, one of those situations where more middlemen would be desirable).