Breidbart Index Explained

The Breidbart Index, developed by Seth Breidbart, is the most significant cancel index in Usenet.

A cancel index measures the dissemination intensity of substantively identical articles. If the index exceeds a threshold the articles are called newsgroup spam. They can then be removed using third party cancel controls.

Cancel Index

Crossposting is the act of posting the same message to multiple newsgroups
Multiposting is the act of posting the same contents multiple times

The principal idea of the Breidbart-Index is to give these methods different weight.^[1] With a crossposted message less data needs to be transferred and stored.And excessive crossposts (ECP) are also a likely beginner's error, while excessive multiposts (EMP) suggest deliberate usage of special software.

The crucial issue is categorizing multiple articles as substantively identical.This includes

byte-for-byte identical messages
otherwise identical postings minimally customized for each group it appears in
advertising the same service
articles that consist solely of the same signature
articles which consist of inclusions of other user's postings, but are otherwise identical

Breidbart Index (BI)

The Breidbart Index of a set of articles is defined as the sum of the square root of n, where n is the number of newsgroups to which an article is cross posted.

Formula

BI=

	m
\sum
	k=1

\sqrt{n_k}

ExampleTwo copies of a posting are made, one to 9 groups, and one to 16.

\sqrt{9}+\sqrt{16}=3+4=7

Breidbart-Index, Version 2 (BI2)

A more aggressive criterion, Breidbart Index Version 2, has been proposed. The BI2 is defined as the sum of the square root of n, plus the sum of n, divided by two. A single message would only need to be crossposted to 35 newsgroups to breach the threshold of 20.

Formula

BI2=

	m
\sum
	k=1

	n_k+\sqrt{n_k

}

ExampleTwo copies of a posting are made, one to 9 groups, and one to 16.

	\sqrt{9
	+

\sqrt{16}+9+16}{2}=

	3+4+9+16
	2

	32
	2

=16

Skirvin-Breidbart Index (SBI, BI3)

The name Skirvin-Breidbart Index and the abbreviation SBI are mentioned in the Spam Thresholds FAQ. However, in hierarchy nl.* this index is called BI3.

The SBI is calculated similar to the BI2 but adds up the number of groups in Followup-to: (if present) instead of the number of groups in Newsgroups:. This encourages the use of Followup-to:.

ExampleTwo posts contain the same text. One is crossposted to 9 groups. The other is crossposted to 16, with four groups in Followup-to:.

	\sqrt{9
	+

\sqrt{16}+9+4}{2}=

	3+4+9+4
	2

	20
	2

=10

BI7 and BI30

In hierarchy de.* the Breidbart index is used with a time range of seven days instead of 45. This is denoted by the abbreviation BI7.

In hierarchy hamster.de.* the Breidbart index is used with a time range of 30 days instead of 45. This is denoted by the abbreviation BI30.

Cancel Index in at.*

This is defined in the FAQ ^[2] of the group at.usenet.cancel-reports.The term used in the Call for Votes ^[3] and in the FAQ is "Cancel-Index".Unofficial abbreviations are CI and ACI.

The ACI of a single post equals 3 plus the number of groups that the post was sent to. The index of multiple posts is the sum of the indices of the individual posts.

Thresholds

According to RFC 1036 only the author of the target message or the administrator of the site that injected the message is allowed to send a cancel.
According to the Spam Thresholds FAQ ^[4] a BI of 20/45 applies to all hierarchies. Series of articles above this limit may be canceled by everyone.
In some hierarchies alternative (stricter) limits were defined through a public vote.
No cancel messages or any derivatives thereof are allowed within free.*.^[5]

In fact a cancel message is a just a non-binding request to remove a certain article.News server operators can freely decide on how to implement the conflicting policies.^[6]

Hierarchy	Cancel Index	Time Range	Limit	Reports	Definition
	BI	45	20	news.admin.net-abuse.bulletins
at.*	ACI	45	11	at.usenet.cancel-reports	^[7]
at.anzeigen.*	ACI	14	4	at.usenet.cancel-reports	^[8] ^[9]
bln.*	BI	45	3		^[10]
de.*	BI	7	5	de.admin.net-abuse.announce	^[11] ^[12]
de.alt.dateien.*	BI	45	1	de.admin.net-abuse.announce
de.markt.*	BI	45	2	de.admin.net-abuse.announce	^[13]
es.*	BI	45	20		^[14]
fr.*	BI	30	4	fr.usenet.abus.rapports	^[15] ^[16]
hamster.de.*	BI	30	3	hamster.cancelreport	^[17]
it.*	BI	45	20	it.news.net-abuse	^[18] ^[19]
muc.*	BI	45	2
nl.*	SBI		10	nl.internet.misbruik.rapport	^[20]
nrw.*	BI	7	2		^[21]
schule.*	BI	14	3	schule.cancelreport	^[22]

Notes and References

https://groups.google.com/group/news.admin.misc/msg/6e7f15c048a71019 <news:36i6hk$3li@panix3.panix.com>
http://www.pfeifer.com/gerald/spam/FAQ.html Spam Cancel in at.* (FAQ)
https://groups.google.com/group/at.usenet.announce/msg/5c062d8beec52a92 <news:CfV$1$at.usenet.cancel-reports$3@usenet.backbone.at>
http://wiki.killfile.org/projects/usenet/faqs/spam/ Spam Thresholds FAQ
http://wiki.killfile.org/projects/usenet/faqs/free/ free.* FAQ
http://wiki.killfile.org/projects/usenet/faqs/cancel/ Cancel Messages: Frequently Asked Questions
https://groups.google.com/group/at.usenet.announce/msg/5c062d8beec52a92 <news:Result-festlegung-bi-06-05-1999@dana.de>
https://groups.google.com/group/at.anzeigen.sonstiges/msg/85adfd5d1ff9287b <news:938889391/18913@usenet.backbone.at>
https://groups.google.com/group/at.usenet.announce/msg/d58b457106d043ba <news:RESULT-Entfernung_von_at.anzeigen.computer.haendler-03.10.1999@orcus.priv.at>
http://home.snafu.de/hweede/dma.htm Die Jobbörse in den Newsgroups: de.markt.arbeit.*
https://groups.google.com/group/de.admin.news.announce/msg/4fc0ae92daa76052 <news:Result-festlegung-bi-06-05-1999@dana.de>
Web site: Fremdcancel-FAQ . 2009-08-14 . https://web.archive.org/web/20070625154346/http://filmateleven.de/cms/?Usenet:Fremdcancel-FAQ . 2007-06-25 . dead .
Web site: Archived copy . 2009-08-14 . dead . https://web.archive.org/web/20110130054729/http://www.s.netic.de/fw/dma-result.txt . 2011-01-30 ., <Result-de.markt.ALL-28.05.1998@dana.de>
http://personal.telefonica.terra.es/web/modestogarrido/usenet/docs/spam.html FAQ: SPAM.ES
http://www.usenet-fr.net/fur/usenet/abus/cancel-faq-fr-1.html Les annulations d'articles (Cancel)
http://al.howardknight.net/?ID=156750021400 Changement des règles d'annulation
http://www.arcorhome.de/newshamster/micha/usenet/rules-de.txt Regelsatz für hamster.de.*
http://wiki.news.nic.it/AiutoCanc Tutto quello che occorre sapere sulla cancellazione
http://www.collinelli.net/antispam/ Pagina Antispam in italiano
Web site: Over cancelrapporten in nl.internet.misbruik . 2009-08-14 . https://web.archive.org/web/20070804154517/http://nl.news-admin.org/info/nlcancel.html . 2007-08-04 . dead .
http://nrw.usenetverwaltung.de/infos/regeln.html Regeln der nrw.*-Hierarchie
Web site: Netiquette.txt. TXT. November 13, 2003. dead. https://web.archive.org/web/20220930124903/http://schule.afaik.de/netiquette/netiquette.txt. September 30, 2022. December 22, 2023.