I just jumped into tagging everything I could right now. I’m went about it by hitting categories with a huge number of posts, skimming through them, then tagging them as I saw fit. I’m nowhere near achieving the elegance Nick has, but I hope to get there. Thanks to him, I can see the power in tagging. Definitely not finished yet.
It’s a long process going through all of the previous posts!
At least I only have eight months compared to your 17 months of posts – crazy!