Stack Exchange

StackExchange is the biggest Q&A network of the 2010s. The software is proprietary (although there are ports like AskBot), and the content is freely licensed (CC-BY-SA).
* Dumps were published every few months at https://archive.org/details/stackexchange
** These dumps were briefly discontinued some time after https://meta.stackexchange.com/questions/389922/june-2023-data-dump-is-missinghttps://meta.stackoverflow.com/questions/424299/stack-overflow-is-no-longer-providing-creative-commons-data-dumpshttps://meta.stackexchange.com/questions/388551/is-se-going-to-be-selling-our-content-for-ai-model-training-and-what-exactly, but were resumed after pressure from various sources on https://meta.stackexchange.com/a/390023.
** On , it was announcedhttps://meta.stackexchange.com/questions/401324/announcing-a-change-to-the-data-dump-process that these dumps would no longer be publicly accessible on archive.org. Instead, they will now be available for download on the settings page after logging in. Additionally, users must agree to new terms before being permitted to download the dumps: "I understand that this file is being provided to me for my own use and for projects that do not include training a large language model (LLM), and that should I distribute this file for the purpose of LLM training, Stack Overflow reserves the right to decline to allow me access to future downloads of this data dump." 
** An unofficial list of all available dumps can be found here: https://meta.stackexchange.com/questions/224873/all-stack-exchange-data-dump-releases
* http://www.stackprinter.com/deleted archives deleted questions
ZIM format:
* https://download.kiwix.org/zim/stack_exchange/
* https://archive.org/search.php?query=stackoverflow.com%20zim
Very inactive questions may be deleted from the site. For example, this question about Internet Explorer 6 was deleted in April or May 2022.http://archive.today/2022.05.14-194521/https://webcache.googleusercontent.com/search?q=cache:nsuiKJiaob0J:https://stackoverflow.com/questions/20916831/navbar-and-iframe-filling-whole-page-internet-explorer-6+&cd=1&hl=en&ct=clnk&gl=de&client=firefox-b-d
== Licence issues ==
User content on Stack Exchange is freely licensed, but the licence has changed over time, and the site makes no attempt to clarify which licence applies to specific content. There have been other actions by Stack Exchange, Inc. over the years that make the details very questionable:
* On , the licence was changed from CC BY-SA 2.5 to 3.0; older content remains under 2.5.
* In 2015, they proposed changing the licence of code snippets from CC BY-SA to MIT on . In response to community backlash over the many legal and practical issues this would cause, the plans were postponed by a month and altered to require attribution, then later postponed indefinitely.
* On , the terms of service were updated. Among other things, the link for the CC BY-SA licence was changed from 3.0 Unported to 4.0 International, but this change was not communicated outwards until September 2019. Older content remains under CC BY-SA 3.0.
** The website footer still claimed that the licence for all user content was CC BY-SA 3.0 until September 2019.
* Until May 2020, the creation page for chatrooms linked to CC BY-SA 2.5 (labeled as 'cc-wiki') as the licence under which all chat messages would be licensed.
* In 2024, the licence of data dumps was changed to exclude commercial use, distribution, and LLM training. Such restrictions are not compatible with CC BY-SA. Note also that the announcement refers to CC BY-SA 3.0, despite the change to CC BY-SA 4.0 several years prior.
* In 2024, Stack Exchange, Inc. removed (or possibly suspended or similar) the account of Luigi Mangione, effectively removing attribution of his content, which would be a violation of the licence (unless it was requested by Luigi). It is unknown how many times this had happened before.
== References ==