OddDog - 9:19 am on Jan 24, 2011 (gmt 0)
A couple of points.
The search engines get the pipe feed from twitter. In this pipe feed the links do not have no follow (sorry for the double negative!).
It is logical for SE´s to include in there algo some sort of qualified measure of social media noise.
I did a test on this and wrote about here at WebmasterWorld