[5] Currently,[update] Stack Exchange is comprised of 173 communities bringing in over 100 million unique visitors each month.

[4][3][10] In June 2021, Prosus acquired Stack Overflow for $1.8 billion, its first complete acquisition in the area of educational technology.

[11] In 2008, Jeff Atwood and Joel Spolsky created Stack Overflow, a question-and-answer website for computer programming questions, which they described as an alternative to the programmer forum Experts-Exchange.

[12] In November 2010, Stack Exchange site topics in "beta testing" included physics, mathematics, and writing.

[16] Stack Exchange publicly launched in January 2011 with 33 Web sites; it had 27 employees[17] and 1.5 million users at the time, and it included advertising.

[22] On April 18, 2013 CipherCloud issued Digital Millennium Copyright Act (DMCA) takedown notices in an attempt to block discussion of possible weaknesses of their encryption algorithm.

[25] As of September 2015[update], "Stack Exchange" no longer refers to the company, only the network of question-and-answer websites.

[28] 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.

[35] 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.

[43] 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.

[4] 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.

Some users were unconvinced that the September 2019 announcement was not a breach of CC BY-SA 3.0 that would have caused its termination, and some answers were not placated by the dateline chosen.

[46] In mid-2023, Stack Exchange made several changes regarding its policies around content generated by artificial intelligence which resulted in a strike of a portion of its volunteer moderators.

[51] The primary purpose of each Stack Exchange site is to enable users to post questions and answer them.

[53] 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.

Elections are called as needed by the Stack Exchange Community Team for a designated number of seats.

[62] Stack Exchange tries to stay up to date with the newest technologies from Microsoft, usually using the latest releases of any given framework.