
What3words

 
What3words is a proprietary geocode system that is designed to identify any location with a resolution of about . The system is owned by What3words Limited, a location services company based in London, England. The What3words system encodes geographic coordinates into three dictionary words; the encoding is permanently fixed. For example, the front door of 10 Downing Street in London is identified by . What3words differs from most other location encoding systems in that it displays three words rather than strings of numbers or letters. 
What3words Ltd. offers a website, apps for iOS and Android, and an API that enables bidirectional conversion between what3words addresses and latitude/longitude coordinates.
History.
Founded by Chris Sheldrick, Jack Waley-Cohen, Mohan Ganesalingam, and Michael Dent, what3words was launched in July 2013. Sheldrick and Ganesalingam originally conceived the idea after Sheldrick struggled to get equipment and bands to musical event locations on time due to inadequate address information, while working as a concert organiser. The company was incorporated in March 2013 and a patent application for the core technology filed in April 2013. In November 2013, what3words raised US$500,000 of seed funding;
Following initial unsuccessful attempts to become profitable as a consumer-focused offering, What3words switched to a business-to-business model. In January 2018, Mercedes-Benz bought approximately ten per cent of the company and announced support for what3words in future versions of the Mercedes-Benz User Experience infotainment and navigation system. The A-Class, launched in May 2018, became the first vehicle in the world with what3words on board.
In March 2021 it was announced that ITV plc had bought a £2.7 million stake in What3words to gain access to advertising space.
In 2018 the company had a turnover of £274,000 and lost £11 million. In the year ending December 2019, the company lost £14.5 million and had reported assets of £24.7 million. By January 2020 the company had reached 100 employees and raised over £50 million from investors.
Design principles.
What3words uses a grid of the world made up of 57 x1012 squares of 3 metres by 3 metres. Each square has been given an address composed of three words. The addresses are available in 43 languages according to the what3words online map (as of May 2020), and the addresses are not translations of the same words.
Each what3words language uses a word-list of 25,000 words (40,000 in English, as it covers the sea as well as land). The lists have been manually filtered to take account of word length, distinctiveness, frequency, ease of spelling and pronunciation, to reduce potential for confusion, and remove offensive words.
The what3words system uses a proprietary algorithm in combination with a limited database; the core technology is contained within a file of about 10 MB. As the system relies on a fixed algorithm rather than a large database of every location on earth, it works on devices with limited storage and no Internet connection. The database is used to assign more memorable words to locations in urban areas. What3words originally sold "OneWord" addresses, which were stored in a database for a yearly fee, but this feature has been cancelled.
The company claims that the what3words algorithm distributes similar-sounding three-word combinations around the world to enable both human and automated error-checking, although these claims are disputed (see Criticism). The result is that if a three-word combination is entered slightly incorrectly and the result is still a valid what3words reference, the location will usually be so far away from the user's intended area that the error will be immediately obvious to both a user and an intelligent error-checking system.
According to Rory Sutherland of Ogilvy (an advertising agency employed by what3words ) in an op-ed piece for the "The Spectator", the advantages of what3words are memorability, error-detection, unambiguous nature of words for most everyday and non-technical uses, and voice input.
Emergency services use.
In February 2020 the system was used for the first time in Scotland by stranded walkers. In the same month it was used for the first time in Australia to rescue a person.
Criticism.
Not an open standard.
Supporters of open standards criticise the what3words system for being controlled by a private business and the software for being patented and not freely usable. 
The company has pursued an assertive policy of issuing copyright claims against individuals and organisations that have hosted or published files of the what3words algorithm or reverse-engineered code that replicates the service's functionality, such as the free and open source implementation WhatFreeWords. The whatfreewords.org website was subsequently taken down following a Digital Millennium Copyright Act (DMCA) take-down notice issued by What3words. This has extended to removing comments on social media which refer to unauthorised versions. In late April 2021, a security researcher was subjected to the threat of a lawsuit from What3words, claiming that linking to the open source reimplementation "WhatFreeWords" violates the company's copyright. "The letter also demanded that he disclose to the [company's lawyers] the identity of the person or people with whom he had shared a copy of the software, agree that he would not make any further copies of the software and to delete any copies of the software he had in his possession."
Words aren't culturally neutral.
Open standards advocate and technology expert Terence Eden has questioned the cultural neutrality of using words rather than the numbers generated by map coordinates. "Numbers are (mostly) culturally neutral." he said, "Words are not. Is mile.crazy.shade a respectful name for a war memorial? How about tribes.hurt.stumpy for a temple?" 
Similar addresses can be close.
The company claims that slightly incorrectly entered three-word combination will be obvious as a mistake. However, security researcher Andrew Tierney demonstrated in 2021 that the What3words algorithm does not sufficiently protect against confusion between nearby locations because it may assign words that are similarly spelled or pronounced, which can limit the value of the system when a precise and unambiguous location is required, like safety-critical applications. Analysis by Tierney showed that close repetitions and the use of plurals occur in physically close locations. The company says that this has a one in 2.5 million chance of occurrence, but Tierney's analysis has highlighted areas where the odds are around 1 in 500.
That similar addresses are purposely far away from each other is seen by others as a disadvantage.
Parody.
The site has been parodied by others who have created services including What3Emojis using emojis, What3Birds using British birds, What3fucks using swear words and What3Numbers using OpenStreetMap tile identifiers.
In popular culture.
In 2018, Stone Brewing Co. launched a beer called, Stone ///Fear.Movie.Lions Double IPA, that was named for the location of its Richmond, Virginia brewery. Also in 2018, What3words appeared in a plot line of .