Categories Or Tags? Sometimes You Can Have Too Many Options

Categories and Tags work basically the same way. You can enter a list of categories or tags on each of their lines for each entry, RapidWeaver will generate a page for each individual category or tag. My previous blog only had categories, I never tagged anything. I'm finding categories so easy to enter that I'm creating a lot of them.
I'm thinking that many of the things I'm entering as categories should be tags and I should reduce my categories to just a few. But what few categories should I use? Or maybe I should just not categorize anything and just tag it all?
Where's the official internet blogging "categories and tagging" guide?
Update 06/07/07 10:26 AM Thanks to EdBrenner on the RapidWeaver forums I read this article on categories and tags. Based on that, i've decided to start tagging entries along with categories. I've started tagging some older stuff, but with a 1000 entries, it's going to take a while

