The dark web is mostly made up of many autonomous devices such as wifi controlled switches and security camera feeds. Then there are the user groups that have basically clung on or evolved from the earliest days of networking with dial up modems. You had to know the name of the group, the number to dial, the modem settings and a password to log into the site. Mostly these sites were populated by computer game enthusiasts swapping hacks to bypass the game protection software, or methods of making free long distance phone calls. As more computer networks came online, it became a popular pastime to try and gain access to university systems and other sites, mostly just for fun, but occasionally to use the extra computing power to run through some problem.
The user groups have devolved into market places for trading drugs, stolen goods, lists of credit card details, pornography, pirated movies, games, and so on. The standard currency is bitcoin, used in belief that it is untraceable. It isn't, but the effort required to link it to an individual is not worthwhile pursuing except by intel agencies.
Enter at your own risk, but I sincerely hope that you don't find anything that piques your interest on the dark web, it will probably be illegal, expensive, or bad for you. Probably a combination of all three.
The one weakness with Tor and the dark web is that every session has to be entered by a legitimate gateway address. Messages and data get bounced around various servers so there is no direct link or contact between the sending and receiving site, but at each end of the connection there is a physical computer connected to an open address. All that rerouting across multiple servers slows your internet connection to a crawl.
It takes time, sometimes as long as 30 seconds to trace a connection between a couple of computers using Tor, but it is fairly trivial to do given the right software and a knowledge of at least one end of the connection. So if you want to attract the attention of the security agencies, feel free to dive in. Just be aware that your activities will not be as anonymous as you might expect given the claims of the hacking fraternity.
Of course, it simply isn't possible to monitor every internet address and connection in real time, so unless you are involved in something really bad, you will probably think you have a remarkably secure connection. Don't forget to have firewalls set and the latest antivirus software installed on your computer. Use Linux if you want anyone on the dark web to take you seriously. Windows will betray you as a noob immediately and probably see your computer overwhelmed with malware in seconds rather than minutes.
Last time I visited my computer was bombarded with 43 malware attacks in under a minute. All of them were blocked, but I spent so much time acknowledging and cancelling the warning messages that kept popping up, it was virtually impossible to actually achieve anything worthwhile. I was looking for an unlock code for an outdated piece of software that I wanted to try out. As it happened the software wasn't of any use, but the dark web was the only source for the code, the program not being supported anymore. So good for that kind of stuff, but beware of the dangers, they are not exaggerated.