I would like to see somewhere that we could define site-specific guidelines and help for users.
- Opinion based questions should be asked on Reddit
- When will.... questions are unsuitable unless...
- Our tag definition guidelines are...
♦ moderators will be able to edit the Help Center page What topics can I ask about here? which (on other Stack Exchange) is often used for site-specific guidelines for questions. Some of the (network-wide) reasons can be found on What types of questions should I avoid asking? as they are not really specific to Cardano.
Tag definition guidelines are often discussed on Meta, so everybody from the community can weigh in. My experience on other Stack Exchange sites is that users creating tags usually don't read the Help Center when they create them.