After reading the report on , written by Gawker's Adrian Chen, democratic senators Charles Schumer of New York and Joe Manchin of West Virginia wrote a letter to U.S. Attorney General Eric Holder, reports. The letter states:

"The only method of payment for these illegal purchases is an untraceable peer-to-peer currency known as Bitcoins. After purchasing Bitcoins through an exchange, a user can create an account on Silk Road and start purchasing illegal drugs from individuals around the world and have them delivered to their homes within days. We urge you to take immediate action and shut down the Silk Road network."

Silk Road is essentially the Amazon.com for illegal drugs on the Internet. Aside from being difficult to access--getting into requires a user to circumvent watchful eyes using the anonymizing network --monetary transactions are also shrouded in anonymity. You can't buy Silk Road drugs with credit cards, PayPal or NFC smartphone payments; the only way to score is by using the "crypto-currency" .

Bitcoins are peer-to-peer based and have no association with banks or governments, and like the BitTorrent technology that inspired their name, bitcoins are regulated by a network of other Bitcoin holders' computers. The free, open-source Bitcoin software is available for Windows, OS X and Linux.

Bitcoins are stored in a digital wallet file, similar to those associated with online banking. There are also third-party wallet services.