Anyone else seen the commercial about it? So basically, you plug this thing into your OBD2 port and it tracks how many miles you drive, what times you drive (kinda like phone peak hours), and it tracks how many sudden stops you make! Haha! I think this is great, especially for those that can't drive (you know who you are...if not watch more tosh.0)! 
http://www.progressive.com/auto/snapshot-common-questions.aspx
http://www.progressive.com/auto/snapshot-common-questions.aspx