It was only a matter of time, but Google is apparently experimenting with embedding AdSense ads in RSS feeds. Yahoo has been experimenting with RSS ads since last fall. We imagine that by the end of the year, most serious publishers will have at least tried ads in their feeds (Forrester analyst Charlene Li hosted two standing-room only sessions on RSS ads at AdTech this week). This could significantly change the complexion of the RSS experience, which has been blessedly light on marketing to this point. On the other hand, here’s hoping that this new money-making opportuninty encourages more publishers to offer full-text RSS feeds. It’ll also be interesting to see if the ad networks can figure how to do a better job of contextually matching the ads to the content (why so many Bob Marley and mortgage ads in Fred Wilson’s feed, for example?)

More coverage: Tony Gentile, Battelle, Technorati, Feedster.