Twitter started out life as an AIM hack that Jack Dorsey added to his pager, Wired reports.

Dorsey had been quite involved in the world of instant messaging, and had launched a dispatch software startup in 1999. Dorsey became quite interested in his friends’ status messages and wanted to see them and set his own remotely at a time when the status message was an ancillary part of the experience — most often used to let people know when you were away from the keyboard and why.

He set about programming a system that would let him fire off an email from his RIM pager which would set his status message and retrieve those of his friends at regular intervals. In 2001, Dorsey said, the timing wasn’t right — the number of people with connected, mobile devices was just too small.

Of course, Dorsey brought the idea back to life while working at Odeo for Evan Williams, and that’s when Twitter really got started. Dorsey has posted some of his initial sketches for Twitter — which he initially called my.stat.us — on Flickr.

mystatus The inspiration for Twitter? AOL Instant Messenger

In the image’s description, posted before “twttr” — as the first iteration was called — went live, Dorsey says:

The 6th year; the idea has finally solidified (thanks to the massively creative environment my employer Odeo provides) and taken a novel form. We’re calling it twttr (though this original rendering calls it stat.us; I love the word.ed domains, e.g. gu.st/). It’s evolved a lot in the past few months. From an excited discussion and persuasion on the South Park playground to a recently approved application for a SMS shortcode. I’m happy this idea has taken root; I hope it thrives.

And thrive it certainly did. Today Twitter is the second largest social network in the world and drives enormous amounts of traffic all over the web.

Who would have thought all this started on a pager?