People are trading bitcoin for goods and services on the illegal marketplaces of the dark web, where the easy, instant flow of the cyptocurrency allows users to tap into their darkest natures--all from the anonymous comfort of their home computers.

Q&A with Nick Bilton on his book, "American Kingpin: The Epic Hunt for the Criminal Mastermind Behind the Silk Road," about Ross Ulbricht's extremely successful (and totally illegal) website.