Mark Follman

Trading in their bright green for black, hundreds of thousands of protesters marched again in Iran on Thursday, urged by presidential challenger Mir Hossein Mousavi to mourn the students killed during demonstrations earlier in the week. Photographer Saeed Kamali Dehghan documented the action for the Guardian in Tehran’s Imam Khomeini square:

NPR’s Mike Shuster reports that members of the Basij, the feared Iranian paramilitary group, have instigated violence under cover of darkness — apparently to help justify a more forceful crackdown against the opposition movement, which by most accounts largely has remained peaceful. One eyewitness report includes a thug exploding an incendiary grenade under a car.

The extraordinary role of digital media in the upheaval remains a hot topic, now including some obligatory contrarianism from the veteran journo corps. (Any hot story in the media tends to provoke both herd-like hyperventilation and a subsequent above-the-fray backlash.) Slate’s Jack Shafer questions the noise-to-signal ratio of the gangbusters #IranElection Twitter stream and points to a potential dark side: “How long before the secret police start sending out organizational tweets — ‘We’re massing at 7 p.m. at the Hall of the People for a march to the Hall of Justice!’ — and busts everybody who shows up?”

Business Week’s Joel Schectman wonders if the “Twitter revolution” has been overblown: “Iran experts and social networking activists say that while Iranian election protesters have certainly used social media tools, no particular technology has been instrumental to organizers’ ability to get people on the street.”

Sure, it’s a worthwhile reminder not to get too utopian about the empowerment of digital technology, especially as the foreign media gets pushed out of the country — but the bottom line is clear: Media control has long been a powerful, essential weapon of the Iranian regime. Twitter, Facebook and blogs increasingly are powerful forces toward neutralizing that weapon. According to Abbas Milani, director of the Iranian Studies Program at Stanford University, Iran has the highest number of bloggers per capita in the world. No matter the outcome of Iran’s historic turmoil, they will continue to be heard.