An advanced (but easy to use) tagging plugin, originally based on ran_tags, but with many improvements, bugfixes, and security enhancements. It has the usual tagging features (listing tags for an article, tag clouds, listing articles for a tag), and it allows you to use standard Textpattern conventions like wraptag / break / class. It is smart about future-dated and “draft” articles, and doesn’t show tags from them. It has clean URL support without modifying .htaccess. It includes tags in RSS / Atom feeds. It shows tags on the admin-side when writing/editing articles. It has admin-side tag maintenance and redirection features.
Connect TXP with Technorati
There are at least a few plugins out there designed to better connect Textpattern powered sites to Technorati. This one just uses categories, or multiple custom fields if you need more than two tags on an article.