Sigh, damn the statistics, I will NEVER make hyperlinks with "here" or "click here" in them! Hide this article from the editors at my job, they will go back to webpages full of blue underlined "here" "here" "here" everywhere! (though I think his experiment is very misleading, as most people scan a webpage and the links stand out, and you don't want a bunch of "here"s otherwise people cant find stuff)
Also, I think a short reason why to follow would have a bigger effect on getting people to take action: "Follow me on twitter for updates on new features" or something, instead of just the blind command. Though if you actually said why someone should follow you on twitter it would probably become apparent why they should not.
Funny, I was just reading a different article about A/B testing
http://www.two-tribes.com/blog/2009/05/31/ab-testing-download-form-50-conversion-increase/