Usenet is a decentralised global network of discussion groups that was one of the first forms of online communication. It was developed in the 1980s to allow people to share information and engage in discussions on a variety of topics including science, technology, politics and entertainment.

Usenet was structured as a collection of "newsgroups" dedicated to specific topics that could be accessed by anyone with a Usenet account. Users could post messages in a newsgroup, which were then forwarded to other users who had subscribed to that newsgroup.

Usenet was one of the first online communities and played an important role in the early development of the internet. However, with the rise of other online platforms such as forums, social media and email, it has lost popularity.