A Newsgroup is a repository within the Usenet system that allows people to post messages and has at times been meant predominantly for sharing news and academic information. However, they are also good places to share files somewhat anonymously.
In many respects, they operate like early message boards, forums, and chat rooms, and have evolved since the very late 70s out of universities.
To the average internet user, even a modern newsgroup looks dated or raw in its format. It doesn’t have the user-friendly vibe or features of modern forums or social media sites.
To pirates and copyright infringers, this is a benefit as it keeps the majority of regular internet users out.
Many have come and gone, even from large corporations, such as the defunct Comcast newsgroups and Google Newsgroups, the latter of which evolved into a more modern message board Google Groups.