It would be amazingly daft to charge less through this system than they are already getting from big commitments. Those big accounts that buy a lot at once would simply go through this. If you're spending more than $10,000 it looks like you can already get a better deal. But if not you'll be able to advertise and not have to complicate it with sales people.

That said, I'm pretty sure NYTimes.com is already getting some pretty high CPMs (> $25 CPM). These self-serve ads won't be as visible as the large branding campaigns, but that's where the real money is.