Cancelbot

A cancelbot is an automated or semi-automated process for sending out third-party cancel messages over Usenet, commonly as a stopgap measure to combat spam.

History

One of the first recorded cancelbots was created in June 1994 by Arnt Gulbrandsen within minutes of the first post of Canter & Siegel's second spam wave, as it was created in response to Canter & Siegel's better known "Green Card spam" in April 1994. Usenet spammers have alleged that cancelbots are a tool of the mythical Usenet cabal.

Rationale

Cancelbots must follow community consensus to be able to serve a useful purpose, and historically, technical criteria have been the only acceptable criteria for determining if messages are cancelable, and only a few active cancellers ever obtain the broad community support needed to be effective.

Pseudosites are referenced in cancel headers by legitimate cancelbots to identify the criteria on which a message is being canceled, allowing administrators of Usenet sites to determine via standard "aliasing" mechanisms which criteria that they will accept third-party cancels for.