Glenn Greenwald on the very real dangers of seemingly innocuous censorship of the Foley beheading video:

Given the savagery of the Foley video, it’s easy in isolation to cheer for its banning on Twitter. But that’s always how censorship functions: it invariably starts with the suppression of viewpoints which are so widely hated that the emotional response they produce drowns out any consideration of the principle being endorsed.

Be sure to read the entire post as Greenwald makes the case for why services like Google, Facebook, and Twitter are now more like public utilities than private entities. A fate they certainly don't want thrust upon them.