A Usenet personality was a particular kind of Internet celebrity, being an individual who gained a certain level of notoriety from posting on Usenet, a global network of computer users with a vast array of topics for discussion. The platform is usually anonymous, although users can get celebrity status, usually by being deemed different from other posters in some way. Since its inception, Usenet newsgroups have attracted a wide variety of people posting all manner of fact, fiction, theories, opinions, and beliefs. Some Usenet posters achieved a certain amount of fame (or infamy) and celebrity within Usenet circles because of their unusual, non-mainstream ideas, or because their writings and responses are considered especially humorous or bizarre. Some Usenet communities became infamous on Usenet as a whole and/or on the wider Internet for posting "indecent material."

Eccentric believers

These individuals (or user-IDs, or pseudonyms) are noted for their eccentric beliefs and theories.

Criminal and eccentric personalities

These individuals (or user-IDs, or pseudonyms) are noted for their criminal, eccentric, paranoid, or threatening behavior, or newsgroup trolling activities.

Unusual personalities

These are individuals (or user-IDs) that are unusual for reasons other than being eccentric.

Other personalities

These people are known for their exceptional and widely read contributions within their respective Usenet communities.