This will automatically make tags with the tagthe.net and yahoo yql services when you save or update a post. Has the option for retagging all post.
This plugin uses the new Yahoo Term Extraction YQL and tagthe.net API to find the most relevant keywords from the content of your post. It will then remove any keywords that you preset and add any global keywords that you have set in the settings screen. It will then add your keywords as tags when you save or update a post. With this you also have the ability to re-tag all posts or tag all post with no tags with the click of a button.
The auto tag system is also completely automatic. It will work anytime you save or update your post and it also works with any autoblogging software you may have that automatically inserts post from RSS feeds.
Read through the list of all the features below to get a feeling of what this plugin can do.
Check out http://josh-fowler.com for more plugins.