"When it first emerged, Twitter was widely derided as a frivolous distraction that was mostly good for telling your friends what you had for breakfast. Now it is being used to organize and share news about the Iranian political protests, to provide customer support for large corporations, to share interesting news items, and a thousand other applications that did not occur to the founders when they dreamed up the service in 2006. This is not just a case of cultural exaptation: people finding a new use for a tool designed to do something else. In Twitter's case, the users have been redesigning the tool itself. The convention of replying to another user with the @ symbol was spontaneously invented by the Twitter user base. Early Twitter users ported over a convention from the IRC messaging platform and began grouping a topic or event by the "hash-tag" as in "#30Rock" or "inauguration." The ability to search a live stream of tweets - which is likely to prove crucial to Twitter's ultimate business model, thanks to its advertising potential - was developed by another start-up altogether. Thanks to these innovations, following a live feed of tweets about an event - political debates or Lost episodes - has become a central part of the Twitter experience. But for the first year of Twitter's existence, that mode of interaction would have been technically impossible using Twitter. It's like inventing a toaster oven and then looking around a year later and discovering that all your customers have, on their own, figured out a way to turn it into a microwave."