system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 how does torrent system work?
gpt
In a traditional situation, you have a Server and a Client. The Server is basically a big computer that handles the request of the Client, if you for example want to download a legal copy of a movie, the server would send it to you.  
That has the advantage of having a clear and simple structure and depending on the server, a reliable source for your movies.  

A torrent system is a peer to peer system, which means there are no dedicated servers, just clients, but everyone fullfils a little bit of the role of the server.  
If you want to download another legal copy of a movie, you would not download it directly, but download a file that basically tells you what you need to download, your client will than ask every other client if they can provide it to you (which is called seeding) and you download it from many different sources.  
The whole system relies on the premise that you make yourself available for seeding after that, so far that you can only download if you seed at the same time.  
It is basically a decentralized version of a server, stretched over many clients.