If you can't believe that governments are using deep packet inspection and block access to popular sites have a look at the 28C3 talk How governments have tried

If you can't believe that governments are using deep packet inspection and block access to popular sites have a look at the 28C3 talk How governments have tried to block Tor - http://www.youtube.com/watch?v=DX46Qv_b7F4 http://www.youtube.com/watch?v=DX46Qv_b7F4 it covers different governments and how they tried to block access to the TOR network