One of the funny happenstances of running a skeptical website that uses Google ads is that I sometimes get ads for services that are not, um, precisely aligned with my goals as a critical thinker. On my site I've seen ads for 2012, for psychics, for all kinds of nonsense (there was even a pro-Moon hoax ad on my page debunking the Moon Hoax!).
I've long held that this is not necessarily such a terrible thing; I think most people on the web are savvy enough to understand that I don't endorse that nonsense. If the ad is particularly atrocious I'll block it, but there are a thousand more elbowing each other out of the way to take its place. It's a losing fight sometimes.
And there are other considerations too... but instead of explaining them here, I'll let Tim Farley of the Skeptical Software Tools website take care of it. He makes a pretty good case that not only are these ads not bad, but they can actually do some good. [Note added after I initially wrote this post: Fraser at Universe Today has more to say on this.]
He's right... but I do have to say that those ads can be downright ookie and skeevy, and I sometimes wish they weren't there at all. When one pops up here, I let the Hive Overmind know and they block it. If you do see an overly egregious one here, let em know. I need to know the URL to which it links (just saying it's an ad for, say, a creationist camp won't help; I need the web address to block it), and then we can block it.
So in my mind the question is still up in the air: are contextual ads evil or not? Food for thought, to get comments rolling: the ad might be for something which is not nonsense, but may be for something I don't care about... like say a particular movie I haven't seen. People wouldn't complain about that ad's content, I suspect. So what to do?