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http://www.webmasterview.com/2011/08/social-networking-history
2. Money, C.: Facebook reaches one billion users (2012).
http://money.cnn.com/2012/10/04/technology/facebook-billion-users
3. CNET: Facebook processes more than 500TB of data daily (2012).
http://news.cnet.com/8301-10233-57498531-93/facebook-processes-more-than-500-tb-of-data-daily
4. Bass, S.: China’s Facebook status: Blocked (2009).
http://abcnews.go.com/blogs/headlines/2009/07/chinas-facebook-status-blocked
5. Dehghan, S.K.: Iran clamps down on Internet use (2012).
http://www.guardian.co.uk/world/2012/jan/05/iran-clamps-down-internet-use