why are people clicking on my ads but not AdSense?
Well for one thing, they only see your ads on your site, right? With personalization and interest-based advertising, they're probably seeing the SAME AdSense ads (or mostly the same) on every other site on the web they visit. Even if they're interested in what the ad has to offer, who says they're going to click on it from YOUR site? Maybe they click on it from a site they visited two sites ago, or maybe it'll take three more impressions on other sites before they get around to it.
I don't think we pay enough attention to this - to some degree it's on Google, because it's the nature of personalization, but frankly they're not doing anything that every other ad network doesn't do as well. And that is, flood the visitors with the same ads everywhere they go.
So to me, the outcomes look like this:
1) Visitor not interested in the ad, just gets more resentful the more he sees it
2) Visitor IS interested in the ad, but given how many websites a person visits in a day, the chances of a click occurring from YOUR site is a lot slimmer than it used to be
3) The visitor clicks on the ad from your site. Even a stopped clock is right twice a day.
Look, say I visit 50 sites a day (and I probably hit a lot more than that) Two years ago, if there was an ad I was interested in, I might see it on, oh, maybe three or four of those sites. So if you were the site running that ad, you had a pretty good shot (statistically) of grabbing that click.
Today I visit 50 sites in a day, and I might see that ad on 39 of them. The odds of getting my click are spread out a lot farther now. And that's assuming no ad blindness/fatigue, and that I'm even interested in it in the first place.
2012 AdSense is not 2007 AdSense, and probably never will be again.
[edited by: netmeg at 2:41 pm (utc) on Apr 9, 2012]