Since feudal days, subjects have hoped that petitioning the sovereign can have great effects. E-mail made writing to politicians easy. Now a new technology is making those missives public. Twitter messages (“tweets” in the jargon) are like public telegrams. No more than 140 characters in length, they can be sent from any computer or mobile phone. Anyone with an account (there are 100m and rising) can send a public message to anyone else by placing the @ sign before a username or a # sign before a topic.That makes it much easier for voters to reach politicians and for politicians to react to them (or at least to pretend to). It helps election organisers too. At its height Barack Obama’s campaign (@barackobama) employed 100 staff working on social media such as Twitter. But now it is catching on elsewhere. In July just four of the world’s top 20 cities for Twitter use were outside America, according to HubSpot, a marketing firm. By January it had grown to eight.
http://www.economist.com/world/international/displaystory.cfm?story_id=16056612