system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: The Pirate Bay

What are the risks of using it? How does it work? What the hell is seeding and leaches?
gpt
Here is a rundown of what Torrenting and ThePirateBay are. The two of them are two different things.

First off, "Torrenting" is an alternative way of downloading files. When you normally download something like an MP3 from a website, you are getting the file directly from the websites computer. For example, if you buy an MP3 from Amazon, you click the download button which then your computer asks Amazon's computer for the file, then Amazon's computer send it directly to you.

Torrenting is a little bit different. To start getting a file by torrenting, you need a program that gets the file. This is called a client. Some examples are utorrent and Bittorrent. When you want a to get a file by torrenting, you need to first tell your client where the files are. While torrenting, many other people who have downloaded it before have the file and there is no one computer where the file comes from. You first go to a website like ThePirateBay. When you find what you are looking for, you click the "magnet" link for it. This tells your client (utorrent, Bittorrent) where the files are and you become a "leecher". Your client then connects to other clients on other people's computers who have that same file and begin sending different pieces of it to you. When you finish getting all of the pieces you become a "seeder" and start sending pieces of that file to other people who are trying to download it. 

The pros of this method are that sharing the files are almost impossible to stop, because once many people are "seeding" it, authorities cannot just simply turn off one main sharing computer, they would need to turn all of them off.

The cons of this process are that if nobody is seeding the file (Either people are greedy and immediately stop the torrent after they finish, or demand for the file has dropped), the download becomes very slow or does not start.

ThePirateBay is not a torrent, but a website where your client can get the info to start a torrent. There are many alternatives to ThePirateBay, like Kickasstorrents and isohunt, but ThePirateBay is so popular because of their resistance to authorities and large variety of torrents.

As for risks, it is actually pretty safe. Whenever you start seeding, your client will only reshare the files if they match what others are sharing exactly. If the file gets infected with a virus, the client will no longer share it. However, people can create a new torrent that has a virus in it. Always check the comments of a torrent on ThePirateBay and see what other people are saying about it before downloading.