Twitter postpones scheduled maintenance to keep service available for Iranian users. Journalists request video on twitter and get deluged with responses. The BBC’s Persian-language television channel said that for a time on Tuesday, it was receiving about five videos a minute from amateurs, even though the channel is largely blocked within Iran. One showed pro-government militia members firing weapons at a rally. “We’ve been struck by the amount of video and eyewitness testimony,” said Jon Williams, the BBC world news editor.