Are there any subjects on Area 51 for which proposals are not allowed?

Question

I know of the following rules for creating a proposal on Area 51:

• The scope must be reasonably well-defined, not too unclear (e.g. "cool stuff"), too opinion-based (e.g. "car reviews"), too broad (e.g. "life on Earth"), or too narrow (e.g. "The 1995 academic misconduct scandal at East Oak Mews High School").
• One must must must come to Area 51 with an already existing community rather than hope to build one on Area 51.
• Proposals that are subsets of existing sites are not acceptable (e.g. Discord API — deleted). These get closed as "This subject is already well-covered by a live Stack Exchange site. We generally do not split off subjects simply to give them their own space."
• Proposals for non-English sites are not currently being accepted.

Other than the criteria above, are there any per se restrictions on site content for an Area 51 proposal? If so, what topics are currently banned? I would expect a proposal for a "Let's organize a lawsuit against Stack Exchange" or "[Specific SE staff member] sucks, amirite?" would get closed for obvious reasons, but I'm interested if there are any non-obvious topics that are not currently allowed in proposals regardless of how well-defined, well-scoped, original, and well-supported by a community they are.

Having a list of banned topics would be helpful to potential proposers as well as the communities that back them. For example, I wouldn't want to go to all the effort of organizing a community, bringing them to Area 51, etc., only to have my proposal closed with a curt "Sorry, due to the political climate, we are not currently accepting proposals for sites about real-life weapons." custom closure.

To be clear, I am asking solely about topic restrictions (e.g. "no sites about fishing, hunting, or weapons"). I'm not asking about clarity requirements, the requirement to have a pre-existing community, not duplicating an existing site, or the requirement to not use sock puppets to artificially inflate proposal stats. Those requirements are already well-defined elsewhere or else are common sense.

Also to be clear, I don't have a specific proposal idea in mind right now or the community to make it happen. I'm asking in general. The question could be rephrased as "What are those topics where I shouldn't even bother to try to define, gather a community, etc. because any attempt to propose a site will be summarily closed due to covering a banned topic?"

This is not a duplicate of Can an Area 51 proposal be "expanded" by the community to include subjects diametrically opposed to the original proposal? because that question is about the appropriateness of expanding a proposal to cover things that are acceptable proposal topics but arguably don't make sense in combination with the original proposal scope. My question is about topics that are completely banned from proposals regardless of whether they are included in the original proposal description or tacked on by the community later.

Answer 1

Yes, there are a few such restrictions against proposals on specific topics. The reasons for restricting these topics essentially boil down to one or more of these main reasons:

• Resource constraints
• The site is not a good fit for the Stack Exchange model
• The topic has been shown to not result in healthy, sustainable sites in the long term

(Note that this answer only covers site topic restrictions, which is what your question asks about; other rules such as the quality of site definition, the requirement for an existing community, or duplicates are not covered here. This also doesn't cover proposals whose topics are "banned" because they've previously involved in voting fraud, per animuson's comment, as those aren't really bans directed at the topic per se.)

• Communities in foreign languages: Stack Exchange has announced that due to resource constraints, they will not be accepting any new proposals for sites in languages other than English. (This does not cover sites about foreign languages whose language medium is English.)
  • To launch any site in a foreign language, the team has decided that Stack Overflow must exist in the language in question, and there must be time to spare from the community managers helping out with that site, which currently isn't the case for any of the foreign languages Stack Overflow is currently in. See Internationalization 'State of the Stack'.
  • To launch Stack Overflow in a foreign language is an onerous process, from translating the entire site UI to other things such as hiring a community manager who speaks the language. Until such time as there are more resources at the company, the team will not be accepting any more "Stack Overflow in [language]" proposals. See Internationalization 'State of the Stack' - Stack Overflow edition.
• [x] Recommendations: While sites in this format, such as Software Recommendations and Hardware Recommendations, exist today, these sites have always been a special case and the general SE model was never designed for recommendations or other subjective-format sites.
  • When the current Software and Hardware Recommendations sites were proposed, there were enough users in the technical communities who took it upon themselves to give this site a shot and allow SE to special-case these proposals. However, the SE team decided that that's as far as they'll take that format, since the engine was never designed for it. See On proposals soliciting reviews, recommendations, comparisons, etc.
• Startups (or Startup Businesses): After two attempts at establishing such a site, both of which failed in beta, the SE team has decided they will no longer accept proposals for this site without significant backing from an organization dedicated to this space.
  • There has been high demand for such a site, but in both of the attempts to launch the site, there hasn't been very much effort from the site's communities to actually help curate the site and engage in community moderation. When the second attempt at this site began beta, SE indicated that the requirements to keep the site running were very low, with only very basic community moderation required. However, that site was unable to muster that, and it was closed. See Why are proposals for a site on startup businesses being closed on sight these days?
• Gender and sexuality studies: Similar to the Startups site above, there have been two failed attempts at launching this type of site, and the SE team has decided they will no longer be accepting proposals for this site without a large organization rallying to create the site from a fresh perspective.
  • In both attempts, it was clear that the site would not work well in the Stack Exchange model. The second attempt at the site ended up devolving into a primarily opinion/personal-advice site, and there was a conspicuous lack of expert-level questions. Also, while the first attempt was entirely focused on being an expert Q&A site, there was very low interest even from site regulars, and many of them later left the site. See Would a "Gender and Sexuality Studies" site be useful?
• Individual blockchain/cryptocurrency sites: For several reasons, the SE team has decided that proposals about single, specific blockchains or cryptocurrencies are no longer allowed. This does not apply to proposals that aim to cover all or most blockchains or cryptocurrencies.
  • From past experience with these proposals, these topics tend attract a lot of attention for a very short, ephemeral period of time, resulting in sites which don't remain healthy and sustainable in the long term. While many current such sites continue to have dedicated communities, quite a bit of the past such proposals have either failed the first two stages of the Area 51 process or were shut down after private beta, as the sites failed to prove long-term sustainability. See Area 51 is no longer allowing individual blockchain, cryptocurrency, or web3 proposals

Honorable mention:

• Linux and other UNIX distributions: While such site proposals are already considered duplicates as their scope is covered under the Unix & Linux site and thus not allowed by that rule, I feel it's worth pointing this out explicitly. Many users who propose sites for other U&L distributions cite the existence of a separate site for Ubuntu as the reason for proposing their site and having it separate from the U&L site. However, Ask Ubuntu was created before the Unix & Linux site, and as such it wasn't a duplicate at the time it was created.
  • For various reasons, including the fact that it is sponsored by Canonical and that it gets as much traffic as a large Stack Exchange site on its own, it was allowed to remain as a separate site rather than be merged into the Unix & Linux site when that was created. Users of both sites also voted against merging the sites. While Stack Exchange has grandfathered Ask Ubuntu due to its nature, it has stated that proposals for other distributions will not be accepted as they are duplicates of the Unix & Linux site. See When there should be separate site for certain Linux distribution?.
  • An exception was made for the later elementary OS site because there was a large community of users ready and willing to use the site, there was a significant difference between the intended audience of that site and that of the Unix & Linux site, and there were more resources available to support it; see Notice: Elementary OS is on-topic on Unix.SE. However, due to limited resources, SE is no longer accepting such proposals, for the reasons in the above bullet's link.