What about ad-blocking at the ISP level?
For some time now, I have been wondering about the viability of setting up a premium ISP business with "transparent" ad-blocking, including half-proxying i.e. fetching the file but never actually delivering it to the browser. Basically I think I'd just need a simple Linux server with some customised Bind zonefiles, and some broadband to re-sell.
I'm sure people would pay extra for no advertisements.