TL;DR: Besides Ask Patents, CS50, Math Overflow, Meta Stack Exchange, and Stack Apps, what open communities that use the Stack Exchange software have non-standard features or use standard features in a unique non-standard way?

By Stack Exchange software, I mean the software that powers Ask Patents, CS50, Math Overflow and Meta Stack Exchange. Regarding the scope of this question, please consider Stack Overflow for Teams as different software.

This question came out while thinking about the current situation of some Stack Exchange Network sites that might take advantage of stuff found in the mentioned sites and other sites that use the same software.

As I understand, the Stack Exchange network was created after the success of the questions and answers community for programmers; Stack Overflow launched in 2008, then there was the "Trilogy" (Stack Overflow, Server Fault, Super User, and the first Meta) named after the Star Wars movies existing at that time. There was the possibility that people created their Q&A site using the same software, known as Stack Exchange 1.0. In 2010 a new process for Q&A site creation based on the "Trilogy" model was launched, requiring people to make a site proposal in Area 51, known as Stack Exchange 2.0.

Some sites use non-standard features or standard features in a non-standard way. By "non-standard way" I mean beyond what the Community Managers can tweak without requiring the intervention of a developer and beyond the recently defined process, like how to make a feature request to customize the Ask Question form.

So far, I have identified Math Overflow, Ask Patents, and Stack Apps.

Are there other sites that have non-standard features or use standard features in a unique non-standard way?


  • 5
    why did you think it necessary to put "As of May 2023" in the title? what restriction are you trying to put on the content here by making that qualification?
    – starball
    Commented May 15, 2023 at 0:36
  • does usage of meta-tags (which are generally not encouraged) count? Ex. Mathematics's soft-question and big-list tags?
    – starball
    Commented May 15, 2023 at 0:39
  • 2
    how is your "rules and enforcement tags" post related? I don't get it. (other than the fact that it's another faq-like post that you wrote)
    – starball
    Commented May 15, 2023 at 1:02
  • Related: Which sites have YouTube embedding on? Commented May 15, 2023 at 4:35
  • Related: The single source of truth for the site list Commented May 15, 2023 at 9:53
  • @starball Regarding "As of May 2023" it is to exclude sites that no longer exist and stuff that was tried but is no longer in use independently if the sites no longer exist or they exist, but the non-standard feature is no longer in use. It is OK to use meta-tags, while they are explicitly approved / allowed by the community nowadays. This is the reason to include the "rules and enforcement tags"; the idea is to focus on stuff that is supported by the community; those that are not explicitly approved" / "allowed" nowadays by the community, are out of scope of this Q&A.
    – user1359324
    Commented May 15, 2023 at 13:13
  • 3
    I find the "May 2023" to be a restriction that will not age well / will age in a way that makes it seem arbitrary (in a way, I think it really is).
    – starball
    Commented May 15, 2023 at 17:07
  • @starball Let's see how this Q&A evolves through this month. P.S. Thank you very much for your enthusiasm shown here.
    – user1359324
    Commented May 15, 2023 at 18:20
  • 1
    A few SE sites have an additional citation helper button in the editing toolbar. Commented May 16, 2023 at 7:20
  • 1
    Minor correction on the history: the trilogy is SO, SF and SU. There was no first Meta, before the creation of this site, MSE, the network meta site was SO's meta.
    – terdon
    Commented May 16, 2023 at 10:27
  • @terdon Thanks. IIRC, the "Trilogy" has four sites, the three main sites + meta. A bit later, I will add the reference.
    – user1359324
    Commented May 16, 2023 at 15:46
  • 1
    @Wicket no, there was no meta for many years, we all used SO's meta for network-wide issues until the Big Meta Split of 2014 when this site was created and SO's meta became a normal child meta, only relevant to Stack Overflow. "The Trilogy" has always meant "Stack Overflow, Server Fault and Super User".
    – terdon
    Commented May 16, 2023 at 15:49
  • uh... do you realize that changing the title from "Stack Exchange communities" to "current communities using SE software" is a significant change in meaning? The first (in my understanding) typically refers to Stack Exchange network sites. The second can refer to... a lot. Ex. Stack Overflow for Teams... or things that scrape SE network sites.
    – starball
    Commented May 16, 2023 at 18:14
  • @starball I just added a clarification about the scope of this question.
    – user1359324
    Commented May 16, 2023 at 22:24
  • 1

2 Answers 2


"Non-Standard" Features

Some of those differences are historical and related to sites being created for already-existing communities. If you like history, have fun digging.

Stack Overflow has a bunch of extra things. A non exhaustive list: Collectives (and as part of that, Articles), had documentation, has the Staging Ground, special plagiarism flags, and (at the time of this writing) several ongoing experiments for content discovery.

"Non-Standard" usage of Features

There are too many to count, really. Each site may have slight differences in etiquette, difference in how much and what type of research effort is required (related to general policy: How should we deal with Google questions? and Embrace the non-Googlers), what types of questions should be closed for reasons to do with or not to do with on-topicality, etc.

But to name some that I find notable (subjectivity and non-exhaustiveness warning):

  • Some sites have sandboxes to get extra review on questions before posting them as actual questions. Ex. Puzzling and Code Golf.

  • Some sites allow crossposting. See What other Stack Exchange sites support crossposting like Mathematics and Math Overflow?.

  • I personally find it interesting the way the following sites use the Stack Exchange model:

    • Puzzling, since presumably, the asker knows the answer (but intentionally does not self-answer)
    • Code Golf, since there's some inherent lack of focus in the language freedom of the common form of challenges there
    • Both the two above sites are also much more tolerable against the "You should only ask practical, answerable questions based on actual problems that you face" and other guidance in /help/dont-ask.
    • Code Review, since questions tend to be more localized than is to taste on other sites.

Requests for Non-Standard Features

(that I am aware of and find noteworthy (subjectivity and non-exhaustiveness warning) (suggestions for additions welcome)):

  • could possibly make an argument for adding tag warnings to this list. would hinge upon whether CMs need help from devs to add new ones, and how many sites use or support the feature. meta.stackexchange.com/q/298887/997587 @V2Blast do you know? (thanks for the edit btw).
    – starball
    Commented May 15, 2023 at 2:01
  • Yes, tag warnings and tag blocks need to be handled by the devs (if the CMs have reviewed the request and agreed that it makes sense to add one).
    – V2Blast
    Commented May 15, 2023 at 2:09
  • 1
    Also, many of the modifications that can be/are made to sites are able to be handled by the CMs, while some others require dev intervention. I don't really think the community would necessarily know which ones the CMs can handle vs. which ones require dev intervention, outside of any we've explicitly mentioned. (And even some of those may have changed, e.g. if the devs have made some of the relevant site settings CM-editable.)
    – V2Blast
    Commented May 15, 2023 at 2:10
  • From our point of view though, a CM lead change or a Dev lead change still follows the same pipeline from our meta I'd think, so 'who' exactly does it dosen't really matter as much as that it can be done Commented May 15, 2023 at 3:07
  • @JourneymanGeek but see this question post's definition of "non-standard". The way this question here is written, it does matter (not that I'm particularly a fan of that definition, but so it is) :/
    – starball
    Commented May 15, 2023 at 3:09
  • Regarding the reputation thresholds for "Private", "Beta" and "Full", considering that this a policy for this, I don't think that it should be considered as "non-standard". I understand that what is standard and non-standard requires a better explanation; something that might help to draw the line is if there is a clear policy and a clear process to customize / change a parameter, and there is no need that an "arbiter" intervene that should be considered "standard". What do you think?
    – user1359324
    Commented May 15, 2023 at 18:34
  • @Wicket hm. define "arbiter". Previously, you defined it as non-CM staff. Is that still what you define it as? And if you're not staff, there's a pretty good catch-all for most of these kinds of change-requests: start a discussion on meta.
    – starball
    Commented May 15, 2023 at 18:46
  • Also, @Wicket, I linked to the site reputation post not for the table comparing public/beta. I linked to it for the section on "Site-specific changes".
    – starball
    Commented May 15, 2023 at 21:06

Part 1: Q&A Sites

Sites that use Q&A features. Area 51 and Stack Apps are included as they use the Q&A software; both use for discussions, bugs, feature requests and support questions.

Area 51

  • The main site is entirely different.
  • The per-site-meta is called Discussion Zone instead of Area 51 Meta.
  • It doesn't have community moderators.

Network sites in private beta

Network sites in public beta

  • Show the Site Stats sidebar box, which includes a link to a proposal in Area 51. For example, this is how Ask Patents Site Stats sidebar box looks like:
    Ask Patents - Site Stats shown on the homepage
  • Only have moderators appointed pro tempore until the site leaves beta, at which point a special graduation election is held.

Ask Patents

prior-art-request tag

Ask Patents prior-art-request tag excerpt

rejected tag

Ask Patents rejected tag excerpt


  • It's an official community for students from a specific class, CS50 from HarvardCS50 meta post.

Math Overflow

Meta Stack Exchange

  • It's simultaneously a main and meta site, with the standard required tags for .

Mi Yodeya

  • It has a Hebrew-alphabet keyboard available when writing or editing posts.

Stack Apps

  • It's simultaneously a main and meta site, with the standard required tags for .

  • It has "top tags" for apps, libraries and scripts.

  • It has a custom homepage showing unique filter buttons "Apps" (that shows questions tagged with apps and libraries, and "Scripts".

  • It has a custom sidebar box: "Get Started"

    Stack Apps Get Started

  • It has a unique form and view: "Register Your V2.0 Application" and "Your apps".

Part 2: Non Q&A Sites

Sites that don't use Q&A features are still part of Stack Exchange; the community creates content.

Data Explorer

  • It's an entirely different site, as users create queries instead of questions and answers.
  • 3
    some of things you've written here aren't really "features" or feature-related at all. Like area51 mods and cs50 community (unless you mean that restricted access to it is a "feature"). Or is my logic wrong? How are those "features"? Also, I don't see why SEDE should be listed.
    – starball
    Commented May 15, 2023 at 0:23
  • 2
    Speaking of "site stats" sidebar, it is not specific to any site, it is shown for every site that hasn't yet left public beta. As soon as it does, it will lose this sidebar, so I don't think it deserves an entry. At least not that specific - I'll try to edit to make it more generalized. Commented May 15, 2023 at 0:33
  • 2
    @OlegValteriswithUkraine I don't think it should even be listed. It's literally standard for every site in beta, right?
    – starball
    Commented May 15, 2023 at 0:37
  • @starball yup, IIRC, it is standard for each and every site that is in beta, so I agree that it shouldn't probably even be listed. I think that it can possibly be salvaged by referring to the feature as common for all beta sites, but I am not sure whether it aligns with the "non-standard" idea of the Q&A. If we interpret it as "features specific to certain sites and states", then there should probably be an entry (and I'd change the title correspondingly as I also agree with your comment under the question - not sure what "non-standard" is supposed to mean). Commented May 15, 2023 at 0:46
  • 2
    And another note: about CS50 - it's not that special either. All sites in private beta (and, apparently, they still are) do not show up and do not have moderator elections. The first election of any given site is when it graduates (it's appropriately called "graduation election"). Commented May 15, 2023 at 0:58
  • 1
    furthering on the point about the inclusion of SEDE, the question's title is "_[...] what current Stack Exchange communities [...]". SEDE has some "community" features (starring), but it's so limited that I'd really hesitate to call it a "community"
    – starball
    Commented May 15, 2023 at 1:14
  • @OlegValteriswithUkraine I don't think that CS50 is still in private beta, as anyone can join (I just joined).
    – user1359324
    Commented May 15, 2023 at 2:21
  • 1
    @Wicket last time I checked, it was still in private beta. However, it has the odd behavior of being able to join that you describe - I am not sure why this is possible, but, to my knowledge, no official answer exists. Commented May 15, 2023 at 3:16
  • 1
    Well, there kinda is an official answer by the venerable Jeremy. Commented May 15, 2023 at 3:19