A Usenet Service Provider (USP) is a company that offers access to Usenet, a worldwide distributed discussion system. Usenet allows users to post and read messages in various newsgroups, which cover a wide range of topics. USPs typically provide the necessary infrastructure and servers to facilitate this access, enabling users to engage in discussions and share files. USPs often offer different subscription plans, which may include features like high-speed access, retention policies, and security options. Users can connect to Usenet through newsreader software, allowing them to browse and participate in newsgroups easily.