Cancelmoose is the username of one of the first anti-spammers. The Cancelmoose was active on Usenet from 1994 to 1995. Using his eponymous cancelbot, he effectively deleted any spam messages caught by his filter. This program was prolific, deleting 1.8 million messages in April 1997.

The Cancelmoose worked anonymously from a computer in Finland, leading to much speculation about his identity. Like other third-party cancelers, critics characterized him as an Internet censor or vigilante, the Cancelmoose's work was highly praised by the newsgroups he came across. The Cancelmoose regarded cancels as an "emergency measure", and retired after developing the software NoCeM (pronounced "No See 'Em), which allowed users to opt-in to hide spam messages marked by trusted users instead.

Usenet is an İnet-based network of discussion boards called newsgroups, where users can read and send posts. It officially started in 1980. Usenet was the precursor to Internet forums and preceded both the World Wide Web and social media, which now host almost all online discussion in the 21st century.^[1][2] The first instance of spamming in 1978 precedes even Usenet, but spam had to be sent manually. However, the commercialization of the Internet in the early 1990s led to floods of automated newsgroup spam.^[3]

In April 1994, two Arizona lawyers mass-mailed spam to Usenet newsgroups, breaking the Internet's unspoken rules against unsolicited advertising and junk mail. CNET would write, years later, that the pair "changed the Internet with one keystroke." The incident solidified automated, commercial spam as an ubiquitous part of the Internet.^[4]

Angered netizens fought back. Cancel messages can be used to effectively delete Usenet posts by instructing the system not to distribute them. However, messages can only be cancelled by the original poster (OP) or the newsgroup's system administrator. Netizens known as "cancelers" engaged in what some characterized as Internet vigilantism. They canceled spam by "fooling" the system, making it appear that their cancel messages came from the OP. This was relatively easy to do and instructions could be found on the Net.^[5]

The process soon became automated, with programs known as cancelbots monitoring newsgroups for spam.^[6] According to Wendy M. Grossman, "cancelers became a feature of life on Usenet".^[7]

The Cancelmoose was one of the first cancelers,^[9] if not the first. In November 1994, this anonymous netizen started using cancelbots to cancel spam,^[10] one of which he named the AutoMoose.^[11] According to Eric S. Raymond's The Jargon File, at a time when cancels were "irregular and disorganized", the Cancelmoose was impartial and quick to reply to feedback, "all without self-aggrandizement or martyrdom." He would then post a notice to the newsgroups, news.admin.policy, news.admin.misc, and alt.current-events.net-abuse.^[12]

The Cancelmoose was popularized by an incident in December 1994 where writer Michael Wolff

In December 1994, writer Michael Wolff sent about 150 different advertisements for his books across Usenet, but the Cancelmoose used an automated cancelbot—also named Cancelmoose—to remove all of his articles. The Baltimore Sun characterized the Cancelmoose as a "digital terrorist" and vigilante. Wolff claimed he was being victimized, but the Cancelmoose responded by saying that the posts were spam due to their quantity, regardless of their content. Wolff also alleged that he had received threatening email from the Cancelmoose, who sent them under Wolff's name. The incident increased the Cancelmoose's popularity; author Jonathan A. Zdziarski wrote that "supporting Cancelmoose was one of the ways many felt they could fight back against spammers."^[10][13] That same month, the Cancelmoose helped come up with one of the first attempts to define spam, as "mass sending of mail to legitimate mailing lists."^[10]

Zdziarski wrote that "a very small group of free speech activists were able to publicly push the Cancelmoose into exile."^[10]

In late 1995, Cancelmoose retired from cancelbot operation. Envisioning a future in which the reader^[14]

Cancelmoose released NoCeM, an alternative program to cancelbots, in September 1995.^[15] NoCeM Disgusted with the current use of cancelbots,^[16]

They used cancelbots to send automated third-party cancel messages for spam and created Cancelmoose, an eponymous bot which identified and reported spam messages. He later created NoCeM. His anonymity led to speculation about his identity, including claims that they were Norwegian or multiple users operating under the same name.

Their identity is known only to a few, and they have been variously described as a single person or a collective.^[10][17] Some sources state that the Cancelmoose used a computer in Finland.^[13] "Nobody knows who Cancelmoose[tm] really is, and there aren't really even any good rumours", read the FAQ of the Usenet newsgroup news.admin.net-abuse in 1995.^[18]

Cancelmoose said that, "I am under no illusions that what I am doing is pure unilateral vigilantism." He advised anti-spammers to never cancel messages based on their content, or they would be severely punished by news.admin.net-abuse.email.^[9]

• "8.12: NoCeM". w3.pppl.gov. Princeton Plasma Physics Laboratory. Retrieved November 16, 2022.
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• Grossman, Wendy M. (1997). Net.wars. NYU Press. ISBN 0-8147-3103-1.
• Grossman, Wendy M. (1995). "War of the Words". Wired. p. 45.
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• Official website