Facebook has, for the first time, revealed the carbon footprint of its operations and its more than 900m users' likes, photo albums and status updates. The data, published on Wednesday, shows that despite the social networking's rising star, its carbon emissions are still a fraction of internet rival Google. Facebook's annual emissions were 285,000 metric tons of CO2 equivalent in 2011, compared with Google's 1.5m tons in 2010. The vast majority of the emissions (72%) come from the company's data centres in the US. The annual footprint for each user that's active monthly is 269 grams, or around the equivalent footprint of a cup of coffee, the company calculated. Facebook also detailed the mix of energy sources that power its data centres. The majority, 27%, comes from coal power, with the rest coming from renewable sources (23%), gas (17%), nuclear (13%) and the remaining 20% uncategorised.