The Scunthorpe problem occurs when a spam filter or search engine blocks e-mails or search results because their text contains a string of letters that are shared with an obscene word. While computers can easily identify strings of text within a document, broad blocking rules may result in false positives, causing innocent phrases to be blocked.
Origin and history 
The problem was named after an incident in 1996 in which AOL's dirty-word filter prevented residents of the town of Scunthorpe, North Lincolnshire, England from creating accounts with AOL, because the town's name contains the substring cunt. Years later, Google's filters apparently made the same mistake, preventing residents from searching for local businesses that included Scunthorpe in their names.
Other examples 
Mistaken decisions by obscenity filters include:
Refused web domain names and email addresses 
- In April 1998, Jeff Gold attempted to register the domain name
shitakemushrooms.com, but he was blocked by an InterNIC filter prohibiting the "seven dirty words" which was active between 1996 and the transfer of control to ICANN. (Shitake is from the Japanese name for the edible fungus Lentinula edodes.)
- In 2000, a Canadian television news story on web filtering software found that the website for the Montreal Urban Community (Communauté urbaine de Montréal, in French) was entirely blocked because its domain name was its French acronym CUM (www.cum.qc.ca); "cum" (among other meanings) is English-language slang for "semen".
- In February 2004, in Scotland, Craig Cockburn reported that he was unable to use his surname (pronounced "Coburn") with Hotmail. Separately he had problems with his workplace email because of the string cialis within his job title of software specialist. He was told by Hotmail to spell his name C0ckburn (with a zero instead of the letter "o"); Hotmail later reversed the ban. In 2010 he had a similar problem registering on the BBC site where again the first four characters of his surname caused a problem for the content filter.
- In February 2006, Linda Callahan, a resident of Ashfield, Massachusetts, was initially prevented from registering her name with Yahoo! as an e-mail address as it contained the substring Allah. Yahoo! later reversed the ban.
- In July 2008, Dr. Herman I. Libshitz was initially unable to get the e-mail address he wanted from Verizon because it contained the substring shit. A spokesperson commented: "As a general rule (since 2005) Verizon doesn't allow questionable language in e-mail addresses, but we can, and do, make exceptions based on reasonable requests. The one from Dr. and Mrs. Libshitz certainly is reasonable and we regret the inconvenience and frustration they've been caused."
Blocked web searches 
- The filter of the free wireless service of the town of Whakatane in New Zealand blocked searches involving the town's own name, because the phonetic analysis used by the filter deemed the "whak" to sound like fuck. The town name is Maori, and in the Maori language "wh" is most commonly pronounced as "f".
- Gareth Roelofse noted: "We found many library Net stations, school networks and Internet cafes block sites with the word 'sex' in the domain name. This was a challenge for RomansInSussex.co.uk because its target audience is school children."
- In July 2011, web searches in China on the name Jiang were blocked following claims on the Sina Weibo microblogging site that former president Jiang Zemin had died. Since the word "Jiang" also means "river" in Chinese, searches related to rivers including the Yangtze (Cháng Jiāng) produced the message "According to the relevant laws, regulations and policies, the results of this search cannot be displayed."
Blocked emails 
- In October 2004, it was reported that the Horniman Museum in London was failing to receive some of its e-mail because filters mistakenly decided that its name was a version of the words horny man.
- Problems can occur with the words socialism, socialist, and specialist because they contain the substring Cialis, the brand name for an erectile dysfunction medication commonly advertised in spam e-mails. Blocking of the word specialist is liable to block emailed résumés and curricula vitae and other material including job descriptions.
Blocked for word with two meanings 
- In May 2006, Ray Kennedy from Manchester in the UK found that e-mails that he had written to his local council to complain about a planning application had been blocked as they contained the word erection when referring to a structure.
- In October 2004, e-mails advertising the pantomime Dick Whittington sent by a teacher from Norwich in the UK were blocked by school computers because of the use of the word Dick, sometimes used as slang for penis.
- In February 2003, members of Parliament at the British House of Commons found that a new spam filter was blocking e-mails to them. It blocked e-mails containing references to the Sexual Offences Bill then under debate, and some messages relating to a Liberal Democrat consultation paper on censorship. It also blocked e-mails sent in Welsh because it did not recognise the language.
- Resumes of magna cum laude graduates have been blocked by spam filters because of inclusion of the word cum, which here is Latin for with but in English is sometimes used as slang for semen.
- Blocked e-mails and web searches relating to The Beaver (based in Winnipeg) caused the publisher to change its name to Canada's History after 89 years of publication. Publisher Deborah Morrison commented: "Back in 1920, The Beaver was a perfectly appropriate name. And while its other meaning is nothing new, its ambiguity began to pose a whole new challenge with the advance of the Internet. The name became an impediment to our growth".
- A councillor in Dudley found an email flagged for profanity by his council's security software after mentioning the Black Country dish faggots.
- In 2007, the Royal Society for the Protection of Birds blocked ornithological terms such as cock (male bird) and tit, Shag and Booby from its discussion forums.
- Residents of Penistone in South Yorkshire.
- Lightwater in Surrey suffered similarly because its name contains the substring twat.
- Residents of Clitheroe (Lancashire, England) have been repeatedly inconvenienced because their town's name includes the substring clit, which (among other meanings) is short for "clitoris".
News articles damaged 
- In June 2008, a news site run by the American Family Association filtered an Associated Press article on sprinter Tyson Gay, replacing instances of "gay" with "homosexual", thus rendering his name as "Tyson Homosexual".
- The word "ass" may be replaced by "butt", resulting in "clbuttic" for "classic" and "buttbuttinate" for "assassinate".
- In December 2011, it was reported that software used by Virgin Media had filtered words including "Arsenal" (for "arse"), and "Canal" (for "anal").
See also 
- Censorship by Google
- Cupertino effect
- Detecting spam
- Medireview – arose as blindly replacing "eval" with "review" in the word "medieval"
- Clive Feather (25 April 1996). In Peter G. Neumann. "AOL censors British town's name!". ACM Committee on Computers and Public Policy.
- Declan McCullagh (23 April 2004). "Google's chastity belt too tight".
- Paul Festa (27 April 1998). "Food domain found "obscene"". News.com.
- "Foire aux questions". radio-canada.ca. Retrieved 24 February 2011.
- Barker, Garry (26 February 2004). "How Mr C0ckburn fought spam". Sydney Morning Herald. Retrieved 24 February 2011.
- Cockburn, Craig (9 March 2010). "BBC fail – my correct name is not permitted". blog.siliconglen.com. Retrieved 24 February 2011.
- "Is Yahoo Banning Allah?". Kallahar's Place. Retrieved 24 February 2011.
- "When your name gets turned against you". Archived from the original on 5 August 2008. Retrieved 3 August 2008.
- "F-Word Town's Name Gets Censored By Internet Filter". Retrieved 27 July 2011.
- Chin, Josh (6 July 2011). "Following Jiang Death Rumors, China’s Rivers Go Missing". The Wall Street Journal. Retrieved 7 July 2011.
- Kwintner, Adrian (5 October 2004). "Name of museum is confused with porn". News Shopper. Retrieved 24 February 2011.
- "Comment headaches". The Peking Duck. 21 November 2004. Retrieved 24 February 2011.
- BBC E-mail filter blocks 'erection' 30 May 2006
- Sam Jones Panto email falls foul of filth filter The Guardian 14 October 2004
- BBC E-mail vetting blocks MPs' sex debate 4 February 2003
- BBC Software blocks MPs' Welsh e-mail 5 February 2003
- Maher, Kris. "Don't Let Spam Filters Snatch Your Resume". Career Journal. Retrieved 11 February 2008.
- "Canada's The Beaver magazine renamed to end porn mix-up". Agence France-Presse. 12 January 2010. Retrieved 12 January 2010.
- Sheerin, Jude (29 March 2010). "How spam filters dictated Canadian magazine's fate". BBC News. Retrieved 29 March 2010.
- "Black Country Councillor Caught up in Faggots Farce". Birmingham Mail. 24 February 2011. Retrieved 24 February 2011.
- "The word 'cock' is banned on RSPB's website". Daily Mail. 13 November 2012. Retrieved 13 November 2012.
- "The 10 best words the internet has given English: From hashtags to LOLs to Cupertinos and Scunthorpe problems, Tom Chatfield picks the most interesting neologisms drawn from the digital world guardian.co.uk".
- http://books.google.co.uk/books?id=3yj_IdO1zPEC&pg=PT15&lpg=PT15&dq=lightwater+surrey+twat+-wikipedia&source=bl&ots=teuchscRQb&sig=LMue_sdXITT6zi3Rae_RkURhByM&hl=en&sa=X&ei=Z71_UfmOLbCN0wX6s4DwAw&ved=0CGUQ6AEwCA = book Unmentionables by Ralph Keyes :: ISBN 987-1-84854-206-8 = Epub ISBN 987-1-84854-456-7
- Frauenfelder, Mark (30 June 2008). "Homophobic news site changes athlete Tyson Gay to Tyson Homosexual". BoingBoing. Retrieved 22 December 2008.
- Moore, Matthew (2 September 2008). "The Clbuttic Mistake: When obscenity filters go wrong". The Daily Telegraph (London). Retrieved 4 April 2010.
- Gye, Hugo (20 December 2011). "What the D***ens is going on? Over-zealous censors filter out favourite TV names (and don't even think of watching an Arsenal game". Daily Mail. Retrieved 20 December 2011.