Green Thing is a community that makes it easy and enjoyable to be a bit greener. Every month you’ll get a different Green Thing to do. All you have to do is do it. October’s Green Thing is Walk Once. Registered users list the number of times they’ve done this month’s “thing”, when they’ve done it and how, and Green Thing estimates how many kilograms of CO2 have been saved. At the end of each month, Green Thing announces the total reduction in CO2 realized by the entire community.