Someone forwarded me this article which I think is pretty neat (although the person who forwarded it to me was freaking out about the privacy issues). Essentially, Target assigns shoppers an internal ID and tracks what the buy. It turns out that they can peg with a great deal of certainty if someone is pregnant and when the baby is due. They can then use this to mail them coupons at specific intervals.
Just shows some of the trends that can reveal themselves when you have tons of data. Scouts take notice. ::rtm::