"Categories": restore erroneously-removed content, separate notes

I thought I was just being pretentious by writing prose in Git, but it actually
just saved me: while rearranging content in my last commit yesterday, I
actually deleted several very important paragraphs! (I was _wondering_ why my
git-wordcount was so low!)

Let's also put the notes/outline for this post in a separate file: I seem to be
more comfortable growing this draft from the top down.