Apparently it's aimed at introverts with Twitter accounts. I can't imagine something less attractive to an introvert than broadcasting your life publicly.
Yeah, I don't broadcast my life -- but I talk about things that are interesting to me, and the Internet gives me a nice medium that I can use without feeling the willpower drain that comes from having constant face-to-face interaction.
[1] http://en.wikipedia.org/wiki/Myers-Briggs_Type_Indicator
[2] http://www.toastmasters.org/
Edit: clarity