hiddentao

Page Tagger is a WordPress plugin which lets you tag your pages just like you do with your posts. It adds a tagging widget in the page-editing view in the admin interface. Page Tagger requires PHP 5.
Detailed information including installation and usage is available at http://www.hiddentao.com/code/wordpress-page-tagger-plugin/
<h3>Known Issues</h3>
<ul>
<li>None at the moment.</li>
</ul>

Page Tagger

Page Tagger is a Wordpress plugin which lets you tag your pages just like you do with your posts. It adds a tagging widget in the page-editing view in …

dangrossman

The Calais Archive Tagger plugin automatically goes through your archives and tags every post you’ve written. The plugin uses the Open Calais API to perform semantic analysis of your post text and suggest tags. If a post already contains a suggested tag, that tag isn’t added, but other new tags found are. It takes about 5 minutes to tag 200 posts.
This plugin requires PHP 5 and the cURL library (both of which are available on most web hosts).
Also see <a href="https://wordpress.org/extend/plugins/calais-auto-tagger/" rel="ugc">WP Calais Auto Tagger</a> for suggesting tags as you write new posts.

WP Calais Archive Tagger

Goes through your archives and adds tags to your posts based on semantic analysis.

Page Tagger vs WP Calais Archive Tagger