From the outside, I like what ReadTheDocs does with Ethical Ads. Because ReadTheDocs's scope is largely limited to technical users, they can deliver "targeted marketing" where they're delivering ads based on the content of their pages rather than user tracking. Also the ads I remember seeing didn't feature attention-grabbing images, just a solid background, the advertiser's logo, and some text about what they're selling. It meshed a lot better with the page content than most ads do.