I've been reviewing tag suggestions for some time and I wanted to check in and talk about this. I'm not going to push for or against a tagging practice, I just want to steer the discussion towards a specific consideration when creating the tagging practice.
This sort of divide between "Am I asking a question that wants to be founded on hard science or out of speculative fantasy potential?", it's definitely a major consideration. So it's definitely something we want to think on. But we want to ask ourselves, "Are tags the right way to do it?"
Remember that tags are not the only tool to distinguish questions or indicate what a question is about. The title, and most importantly, the body of the question, are handy tools to tell you what exactly a user is trying to get. The latter has the biggest advantage in that it gives the user the most room to convey what they want or need. If they want answers that only confer to a specific standard, or that have to abide a certain restriction, that comes in explanation in the question body. A parallel from elsewhere on the network, if you were on Stack Overflow and had restrictions on what options in technology you could use, that would be explained in the question body while the tags would highlight the general content of your question as a whole.
That's not to say that there shouldn't be tags. For example technologies do comprise a good amount of tags on Stack Overflow, for example I myself tagged a bunch of things with the particular form of SharePoint I was working with (and not with MOSS since I didn't have that available in our installation). The important thing is to understand why and when to use tags to identify these things. So some tips, which I probably buried in all this.
- Don't approach tags from the idea of cataloging the kinds of questions you get. Just because the concept of a category exists, doesn't make it meaningful as a tag. Boss fights are a pretty solid concept in gaming but we phased out the "boss-fight" tag on Arqade since it did little beyond just being a tiny label.
- Tags are primarily designed for the benefit of filtering for answerers. It's both a quick sign when browsing the front page, and also allows one to browse within this sub-category. As such, tags should be looked at from the perspective of "Would I really picture answerers browsing around in this tag regularly?" Bonus points for tags that stand alone and don't depend on other tags to give them context.
- Does the tagging reflect normal expectations within the subject matter? We generally blacklist particular tags that reflect the obvious topic of the site, but going past that is the understanding of what one expects in general in the topic space. It's the concept of tagging exceptions to the norm, which leaves the norm as something which doesn't need to be tagged.
- Similar but not identical to the previous, is it an unspoken understanding that doesn't need explicit identification? For example, we don't need "gameplay" as a tag on Arqade because it's readily apparent on any question that is about gameplay, that it is indeed about gameplay. These questions don't make up every kind of question but on questions where it applies, it doesn't even need to be stated in the question body.
My personal immediate thought patterns is that science-based, or perhaps something better named, would be handy when you want to settle that the question must be rooted in the physics and society of our own world. The spectrum of non-scientific, be it full pseudo-scientific or handwave-y, when you're dealing with a concept like building worlds, it's all about creation and so that strikes more as a norm. We shouldn't need additional tags or gradations betwixt them to identify the stuff in between since that I feel is best addressed in question bodies.