antonioandra.de

Enables your blog readers to suggest new post tags or upvote/downvote existing ones. 
Downvoted tags are eventually removed. 
A few more features are on the works as is the expansion of this readme document.
<h3>RoadMap</h3>
Add some frontend feedback; 
Add support for custom taxonomy tagging; 
Synonym dictionary; 
Better documentation, ui and automatic integration.

Author: António Andrade

Enables your blog readers to suggest new post tags or upvote/downvote existing ones.

jaric

Basing on WordPress Plugin “tagthepress” .It using for tag suggestions by Yahoo cas API 
http://tw.developer.yahoo.com/cas/
With this plugin, you will be able to use the the Web service for your posts. Just click on <code>Fetch tags</code> and the title, content and optional excerpt of your post will be analyzed by Yahoo cas API in order to find words that could be useful as tags.
It currently works with English, Chinese

AutoTags

Basing on Wordpress Plugin "tagthepress" .It using for tag suggestions by Yahoo cas API

Author: António Andrade vs AutoTags