For those of you who didn't know, Astronaut Mike Massimino, a mission specialist for STS-125 to the service the Hubble Telescope, has been Twittering his personal accounts of training at http://twitter.com/Astro_Mike. Mike also hopes to Twitter from space.
Mike has now broken the 100,000 follower mark and at last check was at 107,152 followers. That ranks him at number 110 with the most followers on Twitter. Getting that many followers is another fantastic PR coup for NASA. And for those of you who may think Twitter is just a fad I would point out that NASA Watch in the last month received 6% of it's referral traffic from Twitter and that this number is growing each month. It's a social medium worth paying attention to.
Here's a list of some of the NASA Watch, SpaceRef Twitter accounts you can follow:
If you would like a comprehensive list of Space Twitterers you should visit the OnOrbit ColabSpace SpaceMeme list. If you would like to be added to the list then just follow SpaceMeme on Twitter and you'll be added to the list.