On the darknet, Bitcoin is a rather commonly accepted payment method in this day and age. Because of law enforcement agencies cracking down on these users, they have also confiscated a fair amount of Bitcoin in the process. Roughly $4m worth of BTC has been auctioned off on November 5.
One has to commend the US Marshals and other law enforcement agencies for bringing an end to illegal darknet sales. These underground marketplaces allow anyone in the world to buy or sell any good or service one can think of. More often than not, those services rendered are completely illegal, which means law enforcement needs to intervene at the appropriate time.