No, not Andy Richter. We know his face. I'm talking about the deep, booming voice of the guy who does the Twitter Tracker (and before that, many other segments on Late Night). It's Brian McCann, and this short clip below shows him recording some of the loud phrases (he's also a writer on the show and an actor, having appeared on 30 Rock as "the head" in "The Head and the Hair" episode). There's something about the voice that I find annoying yet hilarious and fascinating. It's like the Kool-Aid guy mixed with a demon.