[raceyT]

There are lots of automatic ways to make money like this, even more so on the cost side of a business. They are always going to look great on a spreadsheet but what you're missing is the opportunity cost of all the people that are turned off by the experience. They will fade away in a manner that's harder to measure than CTR.

[nine_k]

I suppose that the decrease in daily / weekly / monthly audience is easily detectable.

Probably it's not very realistic to hand-pick individual ads, unless you run a very niche site. Probably it's still realistic to hand-pick the automatic ad streams you'd agree to show. I suspect the major ad networks allow you to be quite specific.