In Google mail, the price you pay for a cool interface and bazillions of free storage is these little context-sensitive ads at the bottom of each email (I know, this prolly creeps a lot of you out, but whatever, it's an experiment). So I just noticed this ad on the bottom of a gnome desktop-devel thread:

Great deals on Gnomes

(Guess I just added to their googlejuice, didn't I?)