I'll second that! Clearly, a lot of the spam generated is built solely for adsense. It is unbelieveably nauseating from a users point of view.
However ... who says Google wants to stop this sort of spam? Its a huge money maker for them and their single largest weapon against Yahoo and MSN!
Let's not forget that all these built for adsense sites are indexed by MSN, Yahoo and all other SE's too! Google wins no matter what. Its not a moral victory by any stretch, (they have nothing to be proud of with the spam adsense has generated) ... but it sure is a financial victory for them and a major thorn in the side of the other SE's who have to try to cope with this crap.
When Google stops making it so lucrative for spammers to generate all their crap ... maybe the end user will finally see some respectable search results. But we all know this will never happen ... so let the "so called" arms race and the perpetual discussions about "what Google should do about spam" continue. It is a battle which will never end and the end user will always be the loser. They are the real casualties of this "arms race".
Webmasters can only choose which route they want to follow. Personally, I have always maintained that building content is the way to go, but I can also understand the temptation to jump on the spammy adsense bandwagon. In fact, just last night I was thinking it was time to consider adsense. I would never do it for my existing site, but I see no reason not to try to cash in on adsense with some other product. I hear it can be very lucrative!
Unfortunately, relevance and quality content (and other such noble notions) only carry so much weight these days. Its the money the Search Engines are after ... and adsense delivers! Since you can't beat them, you may as well join them.
All aboard! ..... ;)