A Post-it note (or Sticky Note) is a piece of paper stationery with a re-adherable strip of adhesive on the back, designed for temporarily attaching notes to documents and other surfaces. Although now available in a wide range of colors, shapes, and sizes, Post-it notes are most commonly a 3-inch (76 mm) square, canary yellow in color. A unique low-tack adhesive allows the notes to be easily attached and removed without leaving marks or residue.
Post-it notes were invented by 3M's Art Fry, using an adhesive developed by a colleague, Spencer Silver. Until the 1990s, when the patent expired, they were produced only in the 3M plant in Cynthiana, Kentucky. Although other companies now produce sticky or repositionable notes, most of the world's Post-it Brand notes are still made in Cynthiana.
The term "Post-it" and the canary yellow color are registered trademarks of 3M. "Sticky Note", likewise, is a trademark of Société Bic. Generic terms for competitors include "repositionable notes" and "repositional notes". To take advantage of the success of the brand, 3M manufactures other products related to the Post-it concept.
In 1968, Dr. Spencer Silver, a scientist at 3M in the United States, was attempting to develop a super-strong adhesive, but instead he accidentally created a "low-tack", reusable, pressure-sensitive adhesive that has been characterized as "a solution without a problem". For five years, Silver promoted his invention within 3M, both informally and through seminars, but without much success. In 1974, a colleague of his, Art Fry, who had attended one of Silver's seminars, came up with the idea of using the adhesive to anchor his bookmark in his hymnbook. Fry then developed the idea by taking advantage of 3M's officially sanctioned "permitted bootlegging" policy. 3M launched the product in stores in 1977 in four cities under the name "Press 'n Peel", but its results were disappointing. A year later, in 1978, 3M issued free samples to residents of Boise, Idaho, and 94 percent of the people who tried them said that they would buy the product. On April 6, 1980, the product debuted in US stores as "Post-It Notes". In 1981, Post-its were launched in Canada and Europe.
In 2003, the company came out with Post-it Brand Super Sticky notes, with a stronger glue that adheres better to vertical and non-smooth surfaces.
Standard Post-it Brand notes have only partial adhesive coating on the back, along one edge. Similar products are used for specialized purposes with full adhesive coating; the US Post Office uses such yellow address labels to forward mail.
The yellow color was chosen by accident; a lab next-door to the Post-it team only had scrap yellow paper, which the team initially used.
Use in art 
In 2004, Paola Antonelli, a curator of architecture and design, included Post-it notes in a show entitled "Humble Masterpieces". Rebecca Murtaugh, a California artist who uses Post-it notes in her artwork, in 2001 created an installation by covering her whole bedroom with $1000 worth of the notes, using the ordinary yellow for objects she saw as having less value and neon colors for more important objects, such as the bed.
In 2000 the 20th anniversary of Post-it notes was celebrated by having artists create artworks on the notes. One such work, by the artist R. B. Kitaj, sold for £640 in an auction, making it the most valuable Post-it note on record.
In 2012, Turkish artist Ardan Özmenoglu was selected to have a solo exhibition at Bertrand Delacroix Gallery in the art district of Chelsea, Manhattan. The exhibition, titled “E Pluribus Unum” (Latin for “Out of many, one”), opened November 15, 2012 and featured large scale works on Post-it notes.
Use in technology 
Analogues of Post-it notes have also been used in technology in the form of desktop notes which are computer applications developed to allow users to put virtual notes on their computer desktop. These computerized versions of Post-it notes include 3M's own "Post-it Brand Software Notes", Apple's "Stickies", Windows 7's "Sticky Notes"  or other non-free applications like ShixxNOTE. Additionally, some web applications have developed Post-it sort notes for online use.
- Spencer Silver: The guy with the glue
- Donnelly, Tim (23 August 2012). "9 Brilliant Inventions Made by Mistake". Inc. Retrieved 24 August 2012.
- "About Post-it® Brand". Retrieved 2013-02-12. "The Post-it® Note was invented as a solution without a problem: Dr. Spencer Silver developed a special, repositionable adhesive, but the 3M scientist didn't know what to do with his discovery."
- "Inventor of the Week: Art Fry and Spencer Silver". MIT. Retrieved 2007-09-23.
- Petroski, Henry (1992). The Evolution of Useful Things. New York: Alfred A. Knopf. pp. 84–86. ISBN 0-679-41226-3. OCLC 24906856.
- Art Fry and Spencer Silver. "First Person: ‘We invented the Post-it Note’". FT Magazine. Retrieved 2010-12-20.
- "Spencer Silver". Retrieved 2010-12-24.
- "The Evolution of the Post-it Note". 3M. Retrieved 2010-02-13.
- Green, Penelope (2007-07-03). "The all-purpose note that stuck". International Herald Tribune.
- "Why Are Post-it Notes Yellow?". Retrieved 2010-02-25.
- "Post-it Note raises £640". BBC News. 2000-12-27. Retrieved 2007-08-23.
- "Ardan Ozmenoglu “E PLURIBUS UNUM”: Nov 15 – Dec 15". Retrieved 26 October 2012.
- "Windows 7 Features 'Sticky Notes'". Retrieved 2010-12-25.
- "ShixxNOTE network enabled sticky notes program". Retrieved 2012-02-23.
|Wikimedia Commons has media related to: Post-it notes|
- U.S. Patent 3,691,140—Acrylate-copolymer microspheres [adhesive formula]
- U.S. Patent 5,194,299—Repositionable Pressure-Sensitive Adhesive Sheet Material [sheet material]
- Post-it homepage
- BBC news article on 20th anniversary of Post-it notes
- The Rake magazine article on 25th anniversary of Post-it notes
- Post-it Note History—The history of the Post-it note according to 3M