Yahoo! is running a program called ‘Be A Better Planet’ to promote some of their services, including their Yahoo! Answers forum. Residents of each city compete against each other to become America’s greenest city. You could win your city a fleet of hybrid taxis and free compact fluorescent light bulbs (CFLs) for yourself.
Making the pledge with Yahoo! to make greener choices will award you 100 credits. Obtaining your first best answer with Yahoo Answers! will earn you 75 credits in Environmental categories and 10 credits for all others. You will also receive a free CFL light bulb with your first Best Answer (if you’re not familiar with Yahoo! Answers, voters choose the ‘best answer’). Searching via mobile using m.yahoo.com, will earn you an additional 10 credits per search (limit 5 mobile searches per day).
Currently the #1 city is Pelzer, South Carolina.
If you are looking to participate you can sign up here.