AdSense for feeds
In May 2005, Google unveiled AdSense for feeds, a version of AdSense than runs on RSS and Atom feeds that have more than 100 active subscribers. According to the Google Blog, “advertisers have their ads placed in the most appropriate feed articles; publishers are paid for their original content; readers see relevant advertising — and in the long run, more quality feeds to choose from”.
AdSense for feeds works by inserting images into a feed. When the image is displayed by the reader/browser, Google writes the ad content into the image that it returns. The ad content is chosen based on the content of the feed surrounding the image. When the user clicks the image, he or she is redirected to the advertiser’s site in the same way as regular AdSense ads.
AdSense for search
A companion to the regular AdSense program, AdSense for search lets website owners place Google search boxes on their pages. When a user searches the web or the site with the search box, Google shares any ad revenue it makes from those searches with the site owner.
Abuse of Google AdSense
Some webmasters create sites tailored to lure searchers from Google and other engines onto their AdSense to make money from clicks. These “zombie” sites often contain nothing but a large amount of interconnected, automated content (e.g. a directory with content from the Open Directory Project). Possibly the most popular form of such “AdSense farms” are splogs (“spam blogs”), which are centered around known high-paying keywords. Also many sites use the free Wikipedia content to attract visitors. These and related approaches are considered to be search engine spam and can be reported to Google.