Since we already have 7 pages of tags, and some tags are supersets or subsets of the other, I think it would be neat if we have some kind of page or wiki where we can see the relationships among all these tags, in other words, their hierarchy.
So here I am suggesting that we all get together and organize all the tags we have into hierarchy. Feel free to modify the community wiki below.
This is just for fun. You don't have to participate if you don't want to ;)