The secretive nature of dark-web markets makes them difficult to study. But last year a researcher using the pseudonym Gwern Branwen cast some light on them. Roughly once a week between December 2013 and July 2015, programmes he had written crawled 90-odd cryptomarkets, archiving a snapshot of each page.
The Economist has extracted data from the resulting 1.5 terabytes of information for around 360,000 sales between December 2013 and July 2015 on Agora, Evolution and Silk Road 2. In total the deals were worth around $50m. For each transaction we know what was sold, the price in bitcoin, the date of completion, shipping details, the customer's rating and the vendor's pseudonym.
[...] by applying DeepMind's machine learning to our own Google data centres, we’ve managed to reduce the amount of energy we use for cooling by up to 40 percent.