Is there anyway to tell Google, default to these keywords if you haven't spidered a page? I keep getting ads that are totally irrevelant on my forum and blog pages, and sometimes get ads based on a user's name instead of the actual content on the page. I've read several forum posts and articles here before on how to optimize it. I thought I had everything down, but several months later, I'm still having the same problems.
Maybe place the ads further down the page, so it has a greater chance of picking up more relevant content. I also have this problem, pretty bad, on one of my forums. I don't think that Google needs to spider your webpage for it to produce relevant ads, it just goes real-time off of the content on the page.
Are you using content targeting for adsense? https://www.google.com/support/adsense/bin/answer.py?answer=23168
hmm, I had done that after a tip I found here, but I just re-checked it and it was gone. Must have happened in an upgrade. Anyway, we'll see if the ads improve, thanks.