Interesting discussion for sure. I am averse to running google ads on my site but am open to sponsorships from "Thermomix-friendly" businesses. I have a couple of pages on the site that talk about my advertising philosophy. Basically, I think the only ads that will benefit from being on my blog are those that are truly relevant to the specialized audience who visits SuperKitchenMachine.com. Otherwise, as you have all said, the ads are ignored and nobody benefits.
Even though I've been approached by some advertisers, and the allure of accepting network ads is certainly a factor, I've mostly said "no thanks" out of respect for my readers. It's a choice I sometimes wonder about, until I read comments like the ones on this page and then I know I've made the right decision.