I just now stumbled upon this site while looking up "could Kaiju exist?" and I would be interested to know what type of questions to ask on here.
We're here to help you, whether you're a prospective worldbuilder or an experienced geopoet, devise, construct, build, refine, and clarify all aspects of your invented world!
Our basic expectation is that you are coming here because you are a writer (any level of ability), a game designer, a dungeon master, or even just someone who likes to tinker with cultures and histories and maps and geographies and planetary mechanics: in other words, we expect you to be working on some kind of fictional universe, world, planet, or story setting. We deal primarily with questions of systems, properties, materials, and forces. How things work in an invented world. We also deal with invented aspects of culture, religion, mythology, broad sweeps of history, and the like.
We can handle general questions on invented languages (also, and unaesthetically, known as "conlangs"), since these are integral aspects of (most) invented cultures. Though we do have a sister community, Constructed Languages, that can offer deeper insight and guidance.
We don't deal with questions of idle curiosity. Questions like "could XYZ exist" is not a good match for our community, as this is not really a question about your own fictional world. If you are in the process of creating a fictional world or setting, and you're curious about XYZ, then ideally you'd want to consider what XYZ is and how it might fit into your world. Then come here to us and ask "given the constraints of this fictional world, could I fit XYZ into the world in this way?"
Ideally we don't really deal with "real world questions" (like American history, mathematics, geometry, physics, etc). Sometimes they crop up, but we will expect you to provide sufficient worldbuilding context to allow us to give good answers to the question. For example, if your question is one of planetary mechanics, don't ask about the Earth-Moon system. Give us the underlying worldbuilding context: what type of star, how many planets, their sizes, and the basics of the planet-moon(s) you want to ask about along with some kind of approximation of how massive they are, etc. And also note any peculiarities in the Laws of Nature, or differences that may exist between here and there. There are many science-focused communities, which you can find through All Sites. If your question is one of a cultural or social practice, again, help us help you by giving some context: what is it about this particular real world practice resonates with your fictional setting? What is the cultural or social background of your setting like? These will help give you better, more focused responses.
We definitely do not deal with story questions. We're not here to write your story for you, we're not here to develop characters or plots. That's what writing groups are for. We're here for fictional settings only.
We also definitely do not handle questions of third party intellectual property. If you want to ask about Godzilla or Superman or Sauron, we invite you to visit our sister community, Science Fiction & Fantasy for those kinds of questions.
In general: as with any Stack Exchange forum, always check out the Help Centre, which will help you compose good questions and answers. We do have rules and guidelines and community customs (not all of which are written) by which we judge good questions from bad; ideal from those that need work. Then, check out the Tour, which will give you a big picture idea of what this forum is about.
Also here in the Meta secion, you can find loads of helpful resources:
- The Sandbox is a place for you, as a beginner here, to practice your query composing skills. More experienced folks can offer guidance on what works, what doesn't work and what could be changed to improve your questions.
- The Catalogue of Question Types may be of interest as well. Here you can get a more in depth idea of what kinds of questions are a good fit for this community and which are a poor fit.
- How to Write a Perfect Question: title says it all! Lots of helpful guidance on question writing.
- Meta itself is a repository of questions about this forum, how it works, what its rules are, the nuances of rule application. Trawling the Meta is a great way to get an idea not only what what's working well, but also what may not be working as well as it could. There are lots of specific queries, like "why was my question closed" that can help steer you out of the same pitfalls.
We also have some good general purpose worldbuilding resources for the intrepid geopoet: