350 million photographs get uploaded onto the social network every day.
Data centres, the server farms that handle all your snaps and general internet traffic, have emerged as voracious users of electrical power.
They already account for 2% of global power demand, according to research by the campaigning group Greenpeace, conducted several years ago.
The current figure is likely to be higher than that and is expected to rise exponentially in the future as computing increasingly shifts to the "cloud", meaning more stuff gets done over the internet and is stored and processed at data centres.
The trend is a big worry for environmentalists who are concerned about the implications for climate change.
The burning of fossil fuels to generate electricity is a prime source of carbon dioxide emissions - the main gas associated with global warming.
It is also a concern for data centre managers who must wrestle with enormous power bills.
So now the biggies in search and social networking giant need to show their green credentials.
The data centres need to run on renewable energy generated by solar, wind or hydroelectric schemes.
A big part of the cost is cooling so new data centres need to be where cooling is easier – so not in California – they need to be in a sub-arctic location.
A cold climate provides natural cooling for the literally tens of thousands of servers - This saves a lot of electricity.
If you post a status update, upload a photo or do any other kind of activity on Facebook in Europe, it will probably pass through the server farm in Lulea.
Servers are a bit like human beings in the tropics. They like air conditioning and get hot and bothered if the temperature goes too high.
Environmentalists claim the biggies need a bit of a push to get serious about these issues.
The first two facilities Facebook built, both in the US, were in areas where most of the power came from coal-fired generating stations. Not very green
Greenpeace - "Certainly in the US and in many other parts of the world, data centres are being drawn to dirty sources of electricity much like moths to a candle because it's cheap," says Mr Cook.
Power is cheap in states like Virginia and parts of North Carolina because power utilities have surplus capacity thanks of the decline of traditional industries, but cheap power is not necessarily green power. But it is easy as the power companies offered data companies exceptionally low-priced deals.
Google, has become a major investor in wind power, But online retailer Amazon is still the naughty boy in the equation.
Speed of light data is quite literally costing the earth. Coal produces the highest carbon emissions.