Today, Facebook posted their carbon footprint from 2011, with 23% of their energy use clean and renewable power, 27% coal, 17% natural gas, and 13% nuclear. Greenpeace commended Facebook for revealing these numbers, and launched an ‘Unfriend Coal’ campaign to help Facebook users make the switch to renewable energy. Facebook has “set a company goal to derive at least 25 percent of our energy mix from clean and renewable sources by 2015. We know this is going to be a stretch for us, and we’re still figuring out exactly what it will take to get there.”[Source: CNET]