Can a Twitter style site be made in Drupal

I was bored for a couple of hours this weekend and started to wonder if a microblogging site in Drupal.

There are now quite a few microblogging sites online such as Twitter, Jaiku, Pownce and Plurk. I am a heavy user of Twitter as you can see from the right hand column of this site, but with all the network problems and downtime it is having can I make the follow up.

Can I do to Twitter what Facebook did to Myspace?

So I started work on http://www.foocity.com, and after 2 hours work, things look hopeful!