system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How is illegally downloaded material detected/who does the detecting?
gpt
Mostly honey traps.  When you download p2p you are connecting to a someone else, or when using bit torrent lots of people.  They get your IP address, then can track that back to your isp and either ask them to tell you to stop or request your details.