To illustrate and explain my source of confusion, I present you two opposing examples.
Example 1 - less tags
I recently asked this question. Because I play Skyrim on the PC and was expecting the answer to be a console command (until I figured out the answer was to just wait the problem out) I tagged with pc. I have no idea if this particular bug happens on other platforms. As you can see, the PC tag was removed - I added it back, and it was removed again, with the comment
unless you can show that it's a pc-only problem it doesn't get the pc tag
I shrugged and mentally filed away this information since I couldn't find any indication that this was the case or any kind of proof to cite. If the bug happens on the console versions then sure, this Q/A might be useful to them, seems fine to me.
Example 2 - more tags
I know that the purpose of tags is mainly to allow easier filtering and searching within the site. So, when I came across this question I figured that following the assumption "not all questions about minecraft-feed-the-beast are relevant to minecraft" the question didn't need the Minecraft tag. Someone interested in vanilla Minecraft may not necessarily be interested in FTB questions. As you can see from the revision history, not everyone agreed with this, and it emerges that:
site policy is that the tag for the base game is included when the question is about mods for a game
In fact, my tagging changes are mentioned in the comments of that question:
Checking the feed-the-beast tag, it looks like a particular user has been rolling back my edits to include that tag, so perhaps a reminder of this policy would be in order. Ha. – Raven Dreamer♦ 4 hours ago
It's not like I've been systematically rolling back edits, but I have removed the Minecraft tag a few times. Often I don't check the revision history before editing when it seems (at least to me) to be a cut-and-dried change. I've also removed parent tags from some Skyrim questions, where the skyrim-dawnguard (or other expansion tag) has been used in relation to content about that expansion.
What's the problem?
In my eyes, these policies are at odds with each other. The vast majority of Skyrim bugs are probably cross-platform so sure, by all means get rid of the PC tag from a Skyrim bug question. Conversely, the vast majority of FTB questions are not going to be relevant to vanilla Minecraft, so why not follow this same procedure?
Also, I like to consider myself a 'good' use of the site. I've read a lot of past meta content in order to familiarise myself with what to do/not to do, especially when it comes to stuff that's less than intuitive (tagging and allowable questions especially), and I've never come across the policy of questions about expansion content having a tag for the base game. I actually thought that the opposite was true - anything tagged with minecraft-feed-the-beast is already obviously about Minecraft, therefore the Minecraft tag is unnecessary.
So, what I feel needs to be made much clearer is the site's tagging policy. As is clear, trawling through the meta looking for the relevant/important posts leads to an incomplete or even incorrect grasp on the policies.
What is the sites tagging policy and the main rules/exceptions to be aware of? What are the best/important meta posts to read on tagging? Is there a way to consolidate this information so others don't make the same mistakes I have been unknowingly making?
I thought I was helping - this was clearly not the case, so certainly some stuff needs to be clarified.