The volume of information generated by Facebook globally is daunting. In any 20 minutes, Facebook typically sees 1m shared links, 2.7m photos uploaded and 10.2m comments. Facebook also records 7.7m “likes” every 20 minutes, generated not just by users on facebook.com but on more than 2m other sites across the web that have embedded Facebook’s commenting tools.

http://www.guardian.co.uk/technology/2011/jan/04/faceboook-mark-zuckerberg-google