HOME

TheInfoList



OR:

Stack Exchange is a network of question-and-answer (Q&A)
websites A website (also written as a web site) is a collection of web pages and related content that is identified by a common domain name and published on at least one web server. Examples of notable websites are Google, Facebook, Amazon, and Wiki ...
on topics in diverse fields, each site covering a specific topic, where questions, answers, and users are subject to a reputation award process. The
reputation system Reputation systems are programs or algorithms that allow users to rate each other in online communities in order to build trust through reputation. Some common uses of these systems can be found on E-commerce websites such as eBay, Amazon.com, ...
allows the sites to be self-moderating. As of August 2019, the three most actively-viewed sites in the network are Stack Overflow, Super User, and
Ask Ubuntu Ask Ubuntu is a community-driven question and answer website for the Ubuntu operating system. It is part of the Stack Exchange Network, running the same software as Stack Overflow. Members gain reputation based on the community's response (throug ...
. All sites in the network are modeled after the initial site Stack Overflow, a Q&A site for
computer programming Computer programming is the process of performing a particular computation (or more generally, accomplishing a specific computing result), usually by designing and building an executable computer program. Programming involves tasks such as anal ...
questions created by Jeff Atwood and Joel Spolsky. Further Q&A sites in the network are established, defined and eventually if found relevant brought to creation by registered users through a special site named Area 51. User contributions since May 2, 2018 are licensed under Creative Commons Attribution-ShareAlike 4.0 International. Older content, contributed while the site used the Creative Commons Attribution-ShareAlike 3.0 Unported license or the earlier Creative Commons Attribution-ShareAlike 2.5 Unported license, remains licensed under the license in force at the time it was contributed. In June 2021, Prosus acquired Stack Overflow for $1.8 billion, which was the first complete acquisition of Prosus in
educational technology Educational technology (commonly abbreviated as edutech, or edtech) is the combined use of computer hardware, software, and educational theory and practice to facilitate learning. When referred to with its abbreviation, edtech, it often refe ...
.


History


Foundation and growth

In 2008, Jeff Atwood and Joel Spolsky created Stack Overflow, a question-and-answer web site for
computer programming Computer programming is the process of performing a particular computation (or more generally, accomplishing a specific computing result), usually by designing and building an executable computer program. Programming involves tasks such as anal ...
questions, which they described as an alternative to the programmer forum
Experts-Exchange Experts Exchange (EE) is a website for people in information technology (IT) related jobs to ask each other for tech help, receive instant help via chat, hire freelancers, and browse tech jobs. Controversy has surrounded their policy of providi ...
. In 2009, they started additional sites based on the Stack Overflow model: Server Fault for questions related to
system administration A system administrator, or sysadmin, or admin is a person who is responsible for the upkeep, configuration, and reliable operation of computer systems, especially multi-user computers, such as servers. The system administrator seeks to en ...
and Super User for questions from computer
power user A power user is a user of computers, software and other electronic devices, who uses advanced features of computer hardware, operating systems, programs, or websites which are not used by the average user. A power user might not have extensive tec ...
s. In September 2009, Spolsky's company, Fog Creek Software, released a
beta Beta (, ; uppercase , lowercase , or cursive ; grc, βῆτα, bē̂ta or ell, βήτα, víta) is the second letter of the Greek alphabet. In the system of Greek numerals, it has a value of 2. In Modern Greek, it represents the voiced labiod ...
version of the Stack Exchange 1.0 platform as a way for third parties to create their own communities based on the software behind Stack Overflow, with monthly fees. This white label service was not successful, with few customers and slow growing communities. In May 2010, Stack Overflow (as its own new company) raised US$6 million in
venture capital Venture capital (often abbreviated as VC) is a form of private equity financing that is provided by venture capital firms or funds to startups, early-stage, and emerging companies that have been deemed to have high growth potential or which h ...
from
Union Square Ventures Union Square Ventures (USV) is an American venture capital firm based in New York City. The firm has backed more than 130 startups, including Twitter, Etsy, Stripe, Coinbase, Zynga, Tumblr, Stack Overflow, Meetup, Kickstarter, MongoDB, Flur ...
and other investors, and it switched its focus to developing new sites for answering questions on specific subjects, Stack Exchange 2.0. Users vote on new site topics in a staging area called Area 51, where algorithms determine which suggested site topics have
critical mass In nuclear engineering, a critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties (specifically, its nuclear fi ...
and should be created. In November 2010, Stack Exchange site topics in "beta testing" included physics, mathematics, and writing. Stack Exchange publicly launched in January 2011 with 33 Web sites; it had 27 employees and 1.5 million users at the time, and it included advertising. At that time, it was compared to
Quora Quora () is a social question-and-answer website based in Mountain View, California. It was founded on June 25, 2009, and made available to the public on June 21, 2010. Users can collaborate by editing questions and commenting on answers that ...
, founded in 2009, which similarly specializes in expert answers. Other competing sites include
WikiAnswers Answers.com, formerly known as WikiAnswers, is an Internet-based knowledge exchange. The Answers.com domain name was purchased by entrepreneurs Bill Gross and Henrik Jones at idealab in 1996. The domain name was acquired by NetShepard and sub ...
and
Yahoo! Answers Yahoo! Answers was a community-driven question-and-answer (Q&A) website or knowledge market owned by Yahoo! where users would ask questions and answer those submitted by others, and upvote them to increase their visibility. Questions were org ...
. In February 2011, Stack Overflow released an associated job board called Careers 2.0, charging fees to recruiters for access, which later re-branded to Stack Overflow Careers. In March 2011, Stack Overflow raised US$12 million in additional venture funding, and the company renamed itself to Stack Exchange, Inc. It is based in
Manhattan Manhattan (), known regionally as the City, is the most densely populated and geographically smallest of the five boroughs of New York City. The borough is also coextensive with New York County, one of the original counties of the U.S. state ...
,
New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...
. In February 2012, Atwood left the company. On April 18, 2013 CipherCloud issued
Digital Millennium Copyright Act The Digital Millennium Copyright Act (DMCA) is a 1998 United States copyright law that implements two 1996 treaties of the World Intellectual Property Organization (WIPO). It criminalizes production and dissemination of technology, devices, or ...
(DMCA) takedown notices in an attempt to block discussion of possible weaknesses of their encryption algorithm. The Stack Exchange Crypto group discussion on the algorithm was censored, but it was later restored without pictures. , "Stack Exchange" no longer refers to the company, only the network of question-and-answer websites. Instead, the company is now referred to as Stack Overflow. In 2016, Stack Exchange added a variety of new sites which pushed the boundaries of the typical question-and-answer site. For example, Puzzling offers a platform for users who already know the answer to questions to challenge their peers to solve the problems unlike traditional Q–A sites where the poster does not know the answer.


Declining relationship between users and company

In 2016, Stack Exchange announced the second iteration of the Stack Exchange Quality Project, in which they attempt to implement specific important features requested by the community to meet a distinct high-priority set of goals. After users enthusiastically responded with feature ideas, they complained that there was insufficient action on the company's part. In October 2018, the company removed its Interpersonal Skills site from the Hot Network Questions list after a complaint on Twitter, and an employee (who was part of the SRE team, which was not community-facing) posted tweets attacking moderators. On September 27, 2019, a moderator of multiple Stack Exchange sites was dismissed from her moderator position, allegedly connected to behavior associated with upcoming changes to the Code of Conduct (CoC) relating to gender pronouns. Many other moderators resigned or suspended their moderator activity in response to the dismissal. The company responded with two very-poorly-received messages which have since been deleted, and by a slightly less negatively-received apology several days later. In December 2019, the company posted a message, stating that they and the moderator had come to an agreement and expressing regret for any damage to her reputation. Nevertheless, this, plus the sudden departure of multiple community managers (Stack Exchange employees who interact with the community), led to an erosion of trust between the community and the company — convincing many of the site's most prolific users, including many community-elected moderators and a community manager, to depart within the next few months.


2019–2020 licensing change announcements

On September 2, 2019, the terms of service (and the footer of every page served) changed to referencing the "Creative Commons Attribution-ShareAlike" (CC BY-SA) license's 4.0 version instead of its 3.0 version. Users were puzzled as to how Stack Overflow acquired the rights for this relicensing of their past contributions, with some users explicitly stating that they did not intend their contributions to be licensed under CC BY-SA 4.0. Users were concerned that, if the relicensing was found to be a breach of CC BY-SA 3.0, Stack Exchange would have made itself unable to distribute the content under any CC BY-SA license (and that the footer's license statement could be erroneous), and would have to rely on its "perpetual and irrevocable right and license to use, copy, cache, publish, display, distribute, modify, create derivative works and store" the content instead. On September 27, an official Stack Exchange reply stated it had been an "important step", but declined to discuss with the community the legal basis for the relicensing. In March 2020, a post announced that content contributed before May 2, 2018 was available under a CC BY-SA 3.0 licence. In the ensuing discussion, several users asked about the similar situation in August 2010, when Stack Exchange switched from accepting CC BY-SA 2.5 contributions to 3.0. A representative of the corporation noted "we are looking ..to show v2.5 for posts predating this change but cannot commit to it yet". Some users were unconvinced that the September 2019 announcement wasn't a breach of CC BY-SA 3.0 that would have caused its termination, and some answers weren't placated by the dateline chosen. In the ensuing discussion, Stack Overflow staff declined to comment.


Site features


Reputation and badges

The primary purpose of each Stack Exchange site is to enable users to post questions and answer them. Users can vote on both answers and questions, and through this process users earn reputation points, a form of
gamification Gamification is the strategic attempt to enhance systems, services, organizations, and activities by creating similar experiences to those experienced when playing games in order to motivate and engage users. This is generally accomplished thro ...
. This voting system was compared to
Digg Digg, stylized in lowercase as digg, is an American news aggregator with a curated front page, aiming to select stories specifically for the Internet audience such as science, trending political issues, and viral Internet issues. It was launch ...
when the Stack Exchange platform was first released. Users receive privileges by collecting reputation points, ranging from the ability to vote and comment on questions and answers to the ability to moderate many aspects of the site. Due to the prominence of Stack Exchange profiles in web search results and the Stack Overflow Careers job board, users may have reason to game the system. Along with posting questions and answers, users can add comments to them and edit text written by others. Each Stack Exchange site has a "meta" section where users can settle disputes, in the style of MetaFilter's "MetaTalk" forum, because the self-moderation system for questions and answers can lead to significant arguments. Badges are awarded for asking and answering, participating in meta, and for moderating the site. There are bronze, silver and gold badges and appear on users' profile pages as well as their posts.


Moderators and election process

Moderators are responsible for managing the site, such as by following up on flagged posts, locking and protecting posts, suspending users, and deleting the worst posts on the site. According to the Stack Exchange philosophy, they should be minimally involved in the site. They are also expected to lead by example, as well as to show respect to other users. To become a moderator, users have to participate in an election. Elections are called as needed by the Stack Exchange Community Team for a designated number of seats. Users must first nominate themselves and have at least 300 reputation (3,000 on Stack Overflow and 1,000 on Math Stack Exchange), while also being in good standing, such as not having been suspended during the past year. Aside from introducing themselves and explaining why they would be a good moderator, users must also answer questions written by the community. Nominations can be withdrawn at any time. After this, users vote on the candidates in a primary, where the vote tally is made public. The top 10 nominees advance to the election stage, where any user with at least 150 reputation is allowed to vote. A ranked-choice voting system is used where users can rank all the candidates if they wish. Votes are tallied using the Meek STV method (single transferable vote) which allows fractional parts of a vote to be counted.


Bounties

Stack Exchange allows users to donate some of their reputation to help questions receive answers or better answers, as well as to incentivize users to answer. This is called a 'bounty' and can be applied on questions 48 hours after being asked, lasting for 7 days plus a grace period of 24 hours. The minimum bounty is set at 50 reputation, except if the user has already answered the question or has offered a previous bounty on the question. Bounties cannot be cancelled, and reputation cannot be refunded from a bounty, even if the question did not receive an answer.


Criticism

Trustpilot Trustpilot Group plc, is a Danish consumer business operating a review website founded in Denmark in 2007 which hosts reviews of businesses worldwide. Nearly 1 million new reviews are posted each month. The site offers freemium services to busine ...
's page on Stack Overflow, the largest Stack Exchange, shows an average rating of 2.2 stars out of 5, a "Poor" rating. Although 30% of reviewers gave the site a good score, 67% of 136 reviewers gave the site a bad review of 2 stars or fewer. The website was accused by many users of having aggressive moderation that tended to exclude newcomers with lesser programming knowledge.


Technologies used

Stack Exchange uses
IIS IIS may refer to: Organizations * Indian Information Service, of the Government of India * Institute of Information Scientists, a professional association now merged into the Chartered Institute of Library and Information Professionals, UK * Inst ...
, SQL Server, and the ASP.NET framework, all from a single code base for every Stack Exchange site (except Area 51, which runs off a fork of the Stack Overflow code base). Blogs formerly used
WordPress WordPress (WP or WordPress.org) is a free and open-source content management system (CMS) written in hypertext preprocessor language and paired with a MySQL or MariaDB database with supported HTTPS. Features include a plugin architectu ...
, but they have been discontinued. The team also uses
Redis Redis (; Remote Dictionary Server) is an in-memory data structure store, used as a distributed, in-memory key–value database, cache and message broker, with optional durability. Redis supports different kinds of abstract data structures, s ...
,
HAProxy HAProxy is a free and open source software that provides a high availability load balancer and reverse proxy for TCP and HTTP-based applications that spreads requests across multiple servers. It is written in C and has a reputation for bein ...
and
Elasticsearch Elasticsearch is a search engine based on the Lucene library. It provides a distributed, multitenant-capable full-text search engine with an HTTP web interface and schema-free JSON documents. Elasticsearch is developed in Java and is dual ...
. Stack Exchange tries to stay up to date with the newest technologies from
Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washi ...
, usually using the latest releases of any given framework. The code is primarily written in C# ASP.NET MVC using the Razor View Engine. The preferred IDE is
Visual Studio Visual Studio is an integrated development environment (IDE) from Microsoft. It is used to develop computer programs including web site, websites, web apps, web services and mobile apps. Visual Studio uses Microsoft software development platfor ...
and the data layers uses Dapper for data access. The site makes use of URL slugs in addition to numeric
identifier An identifier is a name that identifies (that is, labels the identity of) either a unique object or a unique ''class'' of objects, where the "object" or class may be an idea, physical countable object (or class thereof), or physical noncountable ...
s for question URLs.


Site creation process

Every new site created in the Stack Exchange Network goes through a detailed review process consisting of six steps: # Discussion: The Stack Exchange meta site should provide a forum for discussing potential new ideas labeled a future Stack Exchange site. # Proposal: A public proposal must be drafted and posted so that any member of the community can discuss the proposal and vote on it. This allows a collaborative proposal to emerge over time. The proposal must address these four key issues: ## the topic of the site ## the targeted audience ## forty exemplary questions, upvoted at least 10 times from the community ## 60 followers from the community # Commitment: 200 users interested in the new site are asked to formally commit and support the site by actively participating and contributing to it by asking or answering 10 questions during th
FIRDR
six months of the public beta. # Private Beta: If the concept receives 100% commitment, the site enters the private beta phase, where committed members begin actively using the site and publicizing it. # Public Beta: The site is open to the public for a long period. This allows the creators to ensure that the site reaches critical mass before it is fully launched. # Graduation: The site is evaluated on multiple criteria such as the number of answered questions, new questions per day, and registered users. If it meets these criteria and is deemed "sustainable", it is granted a "graduation" and fully launched.


Notable users


Nobel Prize winners

*
Gerard 't Hooft Gerardus (Gerard) 't Hooft (; born July 5, 1946) is a Dutch theoretical physicist and professor at Utrecht University, the Netherlands. He shared the 1999 Nobel Prize in Physics with his thesis advisor Martinus J. G. Veltman "for elucidating th ...


Fields Medal winners

* Peter Scholze (2018) * Martin Hairer (2014) *
Terence Tao Terence Chi-Shen Tao (; born 17 July 1975) is an Australian-American mathematician. He is a professor of mathematics at the University of California, Los Angeles (UCLA), where he holds the James and Carol Collins chair. His research includes ...
(2006) *
Tim Gowers Sir William Timothy Gowers, (; born 20 November 1963) is a British mathematician. He is Professeur titulaire of the Combinatorics chair at the Collège de France, and director of research at the University of Cambridge and Fellow of Trinity Co ...
(1998) * Curtis McMullen (1998) *
Richard Borcherds Richard Ewen Borcherds (; born 29 November 1959) is a British mathematician currently working in quantum field theory. He is known for his work in lattices, group theory, and infinite-dimensional algebras, for which he was awarded the Fields Me ...
(1998) *
Edward Witten Edward Witten (born August 26, 1951) is an American mathematical and theoretical physicist. He is a Professor Emeritus in the School of Natural Sciences at the Institute for Advanced Study in Princeton. Witten is a researcher in string theory, q ...
(1990) *
Vaughan Jones Sir Vaughan Frederick Randal Jones (31 December 19526 September 2020) was a New Zealand mathematician known for his work on von Neumann algebras and knot polynomials. He was awarded a Fields Medal in 1990. Early life Jones was born in Gis ...
(1990) * Michael Freedman (1986) *
William Thurston William Paul Thurston (October 30, 1946August 21, 2012) was an American mathematician. He was a pioneer in the field of low-dimensional topology and was awarded the Fields Medal in 1982 for his contributions to the study of 3-manifolds. Thursto ...
(1982)


Founders

* Joel Spolsky (co-founder of Stack Overflow) * Jeff Atwood (co-founder of Stack Overflow) *
Ravi Vakil Ravi D. Vakil (born February 22, 1970) is a Canadian-American mathematician working in algebraic geometry. Education and career Vakil attended high school at Martingrove Collegiate Institute in Etobicoke, Ontario, where he won several mathemati ...
(co-founder of MathOverflow)


Other notable scientists and mathematicians

*
Scott Aaronson Scott Joel Aaronson (born May 21, 1981) is an American theoretical computer scientist and David J. Bruton Jr. Centennial Professor of Computer Science at the University of Texas at Austin. His primary areas of research are quantum computing ...
*
Ian Agol Ian Agol (born May 13, 1970) is an American mathematician who deals primarily with the topology of three-dimensional manifolds. Education and career Agol graduated with B.S. in mathematics from the California Institute of Technology in 1992 and ...
*
John Baez John Carlos Baez (; born June 12, 1961) is an American mathematical physicist and a professor of mathematics at the University of California, Riverside (UCR) in Riverside, California. He has worked on spin foams in loop quantum gravity, appli ...
*
Carlo Beenakker Carlo Willem Joannes Beenakker (born 9 June 1960) is a professor at Leiden University and leader of the university's mesoscopic physics group, established in 1992. Early life and education Born in Leiden as the son of physicists Jan Beenakker an ...
* Andreas Blass * Robert Bryant *
Noam Elkies Noam David Elkies (born August 25, 1966) is a professor of mathematics at Harvard University. At the age of 26, he became the youngest professor to receive tenure at Harvard. He is also a pianist, chess national master and a chess composer. E ...
* Matthew Emerton *
Alexandre Eremenko Alexandre Eremenko (born 1954 in Kharkiv, Ukraine; ua, Олександр Емануїлович Єременко, transcription: Olexandr Emanuilowitsch Jeremenko) is a Ukrainian- American mathematician who works in the fields of complex analy ...
*
Joel David Hamkins Joel David Hamkins is an American mathematician and philosopher who is O'Hara Professor of Philosophy and Mathematics at the University of Notre Dame. He has made contributions in mathematical and philosophical logic, set theory and philosophy o ...
(top user on MathOverflow) * James E. Humphreys *
Gil Kalai Gil Kalai (born 1955) is the Henry and Manya Noskwith Professor Emeritus of Mathematics at the Hebrew University of Jerusalem, Israel, Professor of Computer Science at the Interdisciplinary Center, Herzliya, and adjunct Professor of mathematics a ...
*
Anna Krylov Anna I. Krylov (Russian: Анна Игоревна Крылова) is a Professor of Chemistry at the University of Southern California (USC), working in the field of theoretical and computational quantum chemistry. She is the inventor of the s ...
* Greg Kuperberg * Joseph O'Rourke *
Igor Rivin __NOTOC__ Igor Rivin (born 1961 in Moscow, USSR) is a Russian-Canadian mathematician, working in various fields of pure and applied mathematics, computer science, and materials science. He was the Regius Professor of Mathematics at the Univers ...
* Jeffrey Shallit (computer scientist with Erdos number of one) * Peter Shor (inventor of
Shor's algorithm Shor's algorithm is a quantum computer algorithm for finding the prime factors of an integer. It was developed in 1994 by the American mathematician Peter Shor. On a quantum computer, to factor an integer N , Shor's algorithm runs in polynom ...
) * Michael Shulman *
Anders Sandberg Anders Sandberg (born 11 July 1972) is a Swedish researcher, futurist and transhumanist. He holds a PhD in computational neuroscience from Stockholm University, and is currently a senior research fellow at the Future of Humanity Institute at t ...


See also

* MathOverflow *
PhysicsOverflow PhysicsOverflow is a physics website that serves as a post-publication open peer review platform for research papers in physics, as well as a collaborative blog and online community of physicists. It allows users to ask, answer and comment on gr ...
* Q&A software


References


External links

*
List of Stack Exchange sites
{{Fog Creek Software Companies based in New York City Computing websites Creative Commons-licensed websites Internet properties established in 2008 Question-and-answer websites Software developer communities Stack Exchange network