I just finished purchasing our Terra passes. I know some think this is the "easy" way out of being responsible for our carbon footprint. And around here we are very aware of what we do and how it affects the earth. But there are a couple of things that are not very earth friendly. One...we like to travel. LOVE to travel. Our last trip was to Hawaii so I just finished purchasing terrapasses to balance out that flight. I also have a BIG vehicle. We travel a lot, so when we purchased our vehicle we needed something that was SAFE, top priority, and can carry all our stuff. Thus we have a not so fuel efficient vehicle. To balance that out I have purchased a terrapass.
Basically you are donating money to efforts that are green such as wind/solar power, to offset your "not-so-green" living. And while I do believe we are doing all we can here at our house, I recognize that there are areas we are not compromising on. Living consensually we really needed to find a way to make it all work so, for us, terrapass has been the key.