Silk Road is an anonymous online marketplace famed for its range of contraband goods. It requires special anonymity software to be installed before users can access it. Users can only purchase items using the virtual bitcoins currency, which has similar anonymity and privacy measures in place to protect the participants of transactions.

In June 2011 several US senators began an effort to get the site shut down due to its illegal goods. The resulting publicity had the unintended effect of hugely boosting the sites membership and the value of bitcoins.