"Hacked login details, cybersecurity exploits for hire, guns, drugs and ammo -- if there's something shady going on online, chances are it's happening on the darknet.
But for those of us used to opening Chrome or Safari to get online, the darknet is an entirely different beast. How does it work? How is it different to the "surface web"? And what do you need to know before you wade in?
The deep web
The first thing to remember: The darknet is not the same as the "deep web."
The deep web refers to any part of the internet that isn't discoverable by a search engine. But that doesn't mean it's suspicious -- there are plenty of sites you visit in your day-to-day browsing that fall into this category.
When you log in to internet banking, you've navigated to a specific location online, but one that's not served up in Google results. The same goes for the different pages that pop up in webmail services, like Gmail, or academic databases on a university network.
It's hard to estimate just how big the deep web is, but the commonly-cited research (albeit from 2001) puts the deep web at 400 to 550 times the size of the "surface web."
If the surface web is the tip of the iceberg and the deep web is what's below the water, then the darknet is what you'll find deep in the blackest waters below. The darknet is the network itself, whereas the dark web is the content that is served up on these networks.
This is where you'll find the kind of marketplaces that ply their trade in illicit wares -- what security researcher Brian Krebs calls the "hidden crime bazaars that can only be accessed through special software that obscures one's true location online."
Anonymity is the key here. Whistleblowers, activists and political dissidents certainly have good reason to obscure their online location and post with anonymity on the deep web and the darknet, but that level of secrecy is also sought by criminals.
Browsing the darknet
This isn't just a matter of heading to darknet.com and having a snoop -- you'll need specific software and a dedicated browser. Tor (and its dedicated Tor Browser) is probably the most famous of these, though there are others, including I2P and Freenet.
Darknet 101: Your guide to the badlands of the internet - CNET