I came across this video tonight via finehomebuilding.com: http://www.youtube.com/watch?v=E3mzhvMgrLE&feature=player_embedded. This table saw uses a special blade and stopping mechanism to prevent cutting accidents like these. If the saw blade detects electrical conductivity (such as that provided by human skin), it stops the blade within 1/1000th of a second; otherwise, the saw operates as usual since wood is not very conductive. The video is an interesting watch; at the 3:02 mark the creator of the saw uses his finger to demonstrate the effectiveness of the technology.
Plus, the SawStop website actually has a page dedicated to "finger saves". Imagine coming close to losing a finger, and walking away with a cut barely the size of a paper cut.