From Boing Boing –
Quoth Steven Colbert of the Daily Show:
It's just like regular background but with no tagbacks, frontsies or backsies, taken to infinity plus one on opposite day, circle circle dot dot now you've got a cootie shot.
It was first pioneered by Edward R. Murrow.
CrooksAndLiars has the video.
Gotta love the Daily Show!