I decided to give the Ultimate Tag Warrior plugin for WordPress a shot. It's going to be supported natively in the K2 theme that I'm using, and UTW comes highly rated. I was a bit nervous about migrating from the Cat2Tag plugin I'm using now, because I wasn't sure how it would handle ~900 posts that were already categorized. I didn't want to have to re-tag all of those posts. I picked Cat2Tag because it used the Categories themselves to store tags - so if I decided to switch back to Categories, it was just a matter of turning off a plugin, and doing some housekeeping on the now-messy set of categories. I'll assume there will be a magical "convert tags back to categories" function sometime in the future...
Turns out there is a handy dandy "convert categories to tags" function, making the migration to UTW trivial. Now, I'm just nervous about what happens when I want to migrate away from it. For now, I've got the "Automatically convert categories to tags" flag set, so when I add a new post, it takes the categories I enter (via Cat2Tag), and mirrors them in Tags. Duplication for now, but until I'm comfortable with UTW, it's the only way to go :-)
It does provide a nice heatmap of tags, as displayed in the "archives" section. Doesn't provide the heatmap of dates, though, so I'll still be using WP-Heatmap for that.
The compelling reason for looking at UTW is the ability to view boolean sets of tags. I could look at /tag/projects+rants to see all posts that were tagged both "projects" and "rants" - something that wasn't readily possible using straight categories-as-tags.
Just thought of a cool feature to add to UTW - "copy tags from my del.icio.us account" - let me tag my blog posts with the same vocabulary I use to tag the rest of the world.
I did have some fun getting the clean URLs working with UTW, though. The automagic .htaccess updater didn't want to work, so I had to manually add this to my .htaccess:
# Ultimate Tag Warrior RewriteRule ^tag/(.+)$ /index.php?tag=$1 [QSA,L]
Update: Just tweaked the setup a bit... Posts will now be put into one of only 3 categories: "entry", "link" or "aside". I've removed category display from post listings, and replaced with the tag list. I'll try this for awhile, and decide if I want to stick with it before the number of uncategorized entries gets too big.
Update 2: Looks like there's a bug in UTW - if you add only one tag to a post, it generates invalid XHTML (no
after the localtags links). Simple fix for now - just add more than one tag per post :-) Less simple fix - modify line 483 of ultimate-tag-warrior-actions.php to be able to deal with arrays containing just one item. I don't know how to do that at the moment, so will be adding multiple tags.