Google has updated their landing page quality scoring system for AdWords in order to provide a better user experience for those who actually click the ads. This change will target advertisers whose ads lead to a poor user experience. The result is that their minimum bids will increase. What constitutes a poor user experience? Mostly landing pages that consist of nothing but ads or have very little content along with a bunch of ads. From the AdWords blog:

As you may recall, we began incorporating advertiser landing page quality into the Quality Score back in December 2005. Following that change, advertisers who are not providing useful landing pages to our users will have lower Quality Scores that in turn result in higher minimum bid requirements for their keywords. We realize that some minimum bids may be too high to be cost-effective -- indeed, these high minimum bids are our way of motivating advertisers to either improve their landing pages or to simply stop using AdWords for those pages, while still giving some control over which keywords to advertise on. Although it is counter-intuitive to some who hear it, we'd rather show one less ad than to show an ad which leads to a poor user experience -- since long-term user trust in AdWords is of overarching importance.

From time-to-time, we improve our algorithms for evaluating landing page quality (often based on feedback from our end-users), and next week we're launching another such improvement. Thus, over the coming days a small number of advertisers who are providing a low quality user experience on their landing pages will see increases in their minimum bids. It is important to note, however, that the vast majority of advertisers will not be affected at all by this change, as they link to quality landing pages.

Jennifer Slegg provides a detailed analysis at the JenSense blog of who this might negatively affect as well as how it might benefit others. As a "quality publisher" (one who runs AdSense but has quality content to go along with the ads) I'll be watching closely to see how this affects profits.