Stack Overflow is a huge site. It gets about 3.4k questions a day. As such, people need to filter out questions by tags. Otherwise, they won't be able to find questions they can answer, or at the very least will waste a lot of time trying to find them. The traffic is just too great. For this reason, a solid taxonomy of tags is of a crucial importance.
Tags fall into one of two categories:
The scope of Skeptics.SE is huge; we cover nearly all pop science questions.
Like Stack Overflow, Skeptics.SE will need a strong taxonomy of category tags to increase the chance users find questions they can answer. Our category tags will have to be specific enough to be useful, to identify an interest, but broad enough so that one doesn't have to follow twenty tags to follow all the questions he's interested in.
Unlike Stack Overflow, that will be hard to achieve. Most of the category tags on SO are programming languages. Tagging a question about C# with [C#] is pretty intuitive. What do you tag a question about creationism with? Biology, creationism, evolution, religion and intelligent design all seem like good potential tags, but at which point does the tagging become redundant or overly broad? Let's not forget there's also a maximum of five tags we have to work with.
So, what should our category tags be?