The now-defunct Silk Road site, with drugs for sale (AP)

But what is actually on the dark net? Despite all this noise, relatively little is known. It is, of course, incredibly difficult to research. What we do know is that 2.5 million people use the Tor Browser each day. Tor can be used to browse anything online, and is much-used by civil liberties activists, journalists, and suprisise surprise law enforcement themselves. A decent fraction use Tor to get into the dark net, where there are an estimated 60 thousand or so websites an uncensored blend of the good, the bad, and the very very ugly.

The busiest sites on the dark net are probably the notorious and numerous anonymous markets. Here, anything can be bought and sold: class A narcotics ordered with a click, paid for with the crypto-currency Bitcoin, and delivered direct to your home. For my book, The Dark Net, I spent a lot of time on these sites, trying to work out how and why they worked and even going through the process of buying a small amount of cannabis from one known as Silk Road 2.0.

It turns out the key to their success is not clever encryption, or Bitcoin, or even Tor. It's good old-fashioned customer service. Every visitor to the site, after using his or her drug, leaves a piece of written feedback about the gear and gives a score out of 5. It's a little surreal, but users take it pretty seriously, because it creates the genuinely informed competition and choice which keeps the market ticking over:

Decent coke at a reasonable price. Stealthy packaging. 5/5

First order was lost...I got a reship and now im very happy...Heaven is one of the best dealers on the road!!! Very friendly and good communication too. I will be back soon 😉 5/5

More here:

What 'dark net' drug buyers say about their dealers