The issue with human-prescribed metadata is that it is almost never complete. It is almost never consistent. It is barely reliable.
Now that it doesn't take minutes to republish label pages (yay for being hosted on Google's servers), I have gone back and labelled any posts without labels since last November. There are still a bunch of posts requiring labels. That's alright. I don't think I even expose a tag cloud of them anywhere.
Sadly, as I said, they'll invariably inconsistent and incomplete. At least I get to reread posts doing this :)
Oh, and there are a number of dead images that point to an uploaded folder that no longer exists, and dead embedded YouTube videos. Silly Internet.