A cancelbot is an automated or semi-automated process for sending out third-party

cancel message Control messages are a special kind of Usenet post that are used to control news servers. They differ from ordinary posts by a header field named Control. The body of the field contains control name and arguments. There are two historical alterna ...

s over

Usenet Usenet () is a worldwide distributed discussion system available on computers. It was developed from the general-purpose Unix-to-Unix Copy (UUCP) dial-up network architecture. Tom Truscott and Jim Ellis conceived the idea in 1979, and it was ...

, commonly as a stopgap measure to combat

spam Spam may refer to: * Spam (food), a canned pork meat product * Spamming, unsolicited or undesired electronic messages ** Email spam, unsolicited, undesired, or illegal email messages ** Messaging spam, spam targeting users of instant messaging ( ...

History

One of the earliest uses of a cancelbot was by microbiology professor Richard DePew, to remove anonymous postings in science newsgroups. Perhaps the most well known early cancelbot was used in June 1994 by Arnt Gulbrandsen within minutes of the first post of

Canter & Siegel Laurence A. Canter (born June 24, 1953) and Martha S. Siegel (April 9, 1948 – September 24, 2000) were partners in a husband-and-wife firm of lawyers who posted the first massive commercial Usenet spam on April 12, 1994. This event came short ...

's second spam wave, as it was created in response to their "Green Card spam" in April 1994. Usenet spammers have alleged that cancelbots are a tool of the mythical

Usenet cabal The backbone cabal was an informal organization of large-site news server administrators of the worldwide distributed newsgroup-based discussion system Usenet. It existed from about 1983 at least into the 2000s. The cabal was created in an effort ...

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. Currently, the generally accepted criteria (and associated pseudosites) are: By general convention, special values are given in X-Canceled-By, Message-Id and Path headers when performing third-party cancels. This allows administrators to decide which reasons for third-party cancellation are acceptable for their site: * The $alz convention states that the Message-Id: header used for a third-party cancel should always be the original Message-Id: with "cancel." prepended. * The X-Canceled-By: convention states that the operator of a cancelbot should provide a consistent, valid, and actively monitored contact email address for their cancelbot in the X-Canceled-By: header, both to identify the canceler, and to provide a point of contact in case something goes wrong or questions arise regarding the cancelbot's operations. * The !cyberspam convention states that specific pseudosites should be given within the cancel message's Path to identify them as complying with certain cancel criteria, see above.

References

Usenet {{Compu-network-stub

History

Rationale

See also

References