Google is test-driving the use of its AdSense program in RSS feeds, with Longhorn Blogs serving as the initial testbed. "I can't talk a whole lot about this yet," writes Longhorn blogger Robert McLaws. "I can tell you that this is a pilot program for a new AdSense product that Google is looking into. Like all of their tests, it may disappear for a while, or be discontinued altogether. Right now LonghornBlogs.com is the only site running this test. That will probably change in the next few days as their other alpha testers bring their systems online, but for now, we're it."
JenSense, ProBlogger and Chris Pirillo also weigh in, with Lockergnome's Pirllio noting that the feed doesn't work properly in NewsGator. That's probably the kind of issue Google will focus on surfacing and fixing through the use of the beta test sites.