For anyone trying out WordPress and interested in keeping their tags alive: don’t. Ultimate Tag Warrior is completely broken with WordPress 2.1 and you can lose all your tags by upgrading to WordPress 2.1. In the more recent SVN revisions of WordPress 2.1, any time a comment is added, deleted, or unapproved, you lose all the tags for that particular post. It’s a damn shame, because UTW is an excellent plugin, and WordPress 2.1 is a big improvement over 2.0.
Bunny’s Technorati Tags is a more basic tagging solution, but it’s verified working on WordPress 2.1. If you can figure out how to switch from UTW to Bunny’s TT you can easily switch back when Christine releases a new version of UTW that’s compatible with WP 2.1 via her import from custom-field feature. Just be very careful, make database backups, and use Google when you get stuck.
Get the fix here.