Haffner writes "Protests in Cairo, Egypt have now reached the tens of thousands. Police have deployed water cannons and tear gas. I am writing this live from Cairo, where I witnessed a throng of 1000-3000 march towards Tahrir Square in downtown Cairo. I also witnessed 300-500 protesting on one of the bridges heading downtown. Most importantly, twitter has been blocked by many national carriers." Why Twitter? As reader pinkushun writes "Using Twitter and Facebook, the people instigated a series of fast-moving, rapidly shifting demos across half a dozen or more Egyptian cities. The police could not keep up – and predictably, resorted to violence. Sadly this has led to three known deaths thus far." Update: 01/26 02:05 GMT by T : Jake Appelbaum is tweeting up a storm about the state of the active filters.