So what does this have to do with Gavin? Why's he suddenly pushing a Yahoo ad campaign that's disguised as greeniness but is actually just a trick to get us to use their websites? Why, no ulterior motive at all. He just LOVES the environment, and is willing to go to any length to promote its preservation -- EVEN SENDING OUT A NEWSLETTER!
Also, the city with the most signups wins a fleet of hybrid taxis.