How I choose my tags

I am working of something of a keyword search here, in addition to larger categories, kind of like web-page Meta tags. The idea is that if I can remember any keywords at all I can find my article easily, but if I have only a vague idea of the subject then it's much harder - I have to browse the months around when I (almost always incorrectly) remember posting it. The larger categories aren't that useful either, because they'll return too many hits.
Tags Meta-blogging