and andrea peterson. technology reporter for the "washington post." istening who may not know a great deal about this, what is bitcoin? why use it instead of real money? >> hi. so thanks so much for having me on, craig. so bitcoin actually refers to both an online payment technology and a digital currency that's used by that payment technology. the two big differences are that it is decentralized and peer to peer. there's not some big company propping it up or dealing with shareholders. and that it does use digital currency also termed bitcoin, it's not the same thing as the u.s. dollar. >> alex, you've been looking at a connection between bitcoin and the internet. still corrode the online drug marketplace that was shutdown. what have you found so far about the bitcoin culture? >> first of all, out of fairness i would separate it. one of the main things i found was that there's very little connection between bitcoin and the black market in terms of them being inexplicably tied together. >> everyone using bitcoin is not buying weed? >> absolutely not. t