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.