It looks the days of most feeds having no ads are quickly coming to a close. I just noticed Google AdSense ads in the feed from The Unofficial Apple Weblog (TUAW). As has already been noted, Google been letting a few sites test out this new feature recently. When Google turns on this feature for all AdSense users I expect the flood gates will be thrown open and feeds without ads will quickly become the minority. Just this week I’ve gone from one of the 80+ feeds that I read having ads to four. I don’t know how long Google is going leave this feature in the testing phase, but I’d expect that by the end of May ad free feeds will become pretty rare.
When you combine the idea of Google allowing ads in feeds and their purchase of Urchin you end up with a strong FeedBurner competitor.
UPDATE 5:00pm 27 Apr 2005: Now my PubSub feed has AdSense ads.