Ads in Google Reader

Right on the heels of this post by Steve Rubel, Google Reader just put ads up in their feed. I have no idea why he didn't think that Google would be able to run ads, but they apparently can. This pisses me off, because now the beautiful clean look of Reader is gone, but the good news is that there aren't ads in every feed for some reason. The only one I have noticed so far is in the WSJ's Numbers Guy blog, does Google have to ask for permission to put ads up? Hopefully, because if there are ads in every single post, then I might look for another reader.