From Twitter to texting, the world's gone hashtag crazy, with the New York Times calling it the "secret handshake". It's even a common occurrence in advertising, with campaigns inviting people to join the discussion that way.
Looking into the history of the hashtag the NYT detailed how it all came about: supposedly it was kickstarted by Chris Messina, a developer at Google who suggested on Twitter in August 2007 that they all start hashtagging tweets that can then be organised and searched easily. Now, it's more about adding a layer of depth to a tweet or message - as Messina says, "you kind of have to be in-the-know. So it's one of those jokes where you're like, ‘Oh, I see what you did there, because you're on Twitter and I'm on Twitter.'"
And in something which even I had no idea existed, apparently hardcore Twitter users even have a gangsign (so to speak), where they cross their index and middle finger on one hand with the same two fingers of the other - almost like a hashtag. Which might make anti-Twitterites all the more loathing of the service. [NY Times]
Image credit: Robert Scoble