Don’t look for a second Twitter revolution in Iran. With protests spreading there, authorities have ramped up their censorship regime, blocking opposition websites, slowing down the Internet, and censoring text messages. Reports also say mobile-phone traffic is badly disrupted. It’s all part of an effort to make organizing protests much harder. Meanwhile, Secretary of State Hillary Clinton has blasted the regime for its crackdown following the shooting death of a protester in Tehran and the house arrest of key opposition leaders including Mir Hossein Mousavi.