Vietnam sentenced a music teacher to 11 years in prison on Friday for Facebook posts that allegedly undermined the one-party state, which has been accused of tightening the noose on online dissent. Communist Vietnam has long jailed its critics but has come under fire recently for targeting users on Facebook, a popular forum for activists in the country where all independent media is banned. Nguyen Nang Tinh is the latest activist jailed for his Facebook comments, including posts about police brutality, land rights, and a Taiwanese steel firm that dumped toxic sludge into the ocean, killing masses of fish off the coast of Vietnam.