If just noticed on one of my sites that there is a shopping cart image in a text only Adsense ad. Hovering over it shows that the merchant accepts Google checkout, is this a new thing and could it improve CTR (I normally don't notice Adsense but this one caught my eye)?
I just saw a post and sample ad here also: http://www.indiculture.com/fashion/2007/02/12/now-adsense-with-google-checkout/