kegentile

This plugin will create a tag cloud for a specific author. This will allow a visitor on your site to drill deep down into an author’s specific content.
It uses all of the same parameters as wp_tag_cloud(), but adds an additional one for the author_id. When the author_id is passed an integer of a published author that has tagged his or her posts, a tag cloud will be generated.
It will also create a new permalink structure on your site of
www.yoursite.com/author/author-slug/tag/tag-slug
***Note: that you must be using any custom permalink structure for this plugin to function. Also, custom taxonomies is currently not functioning with this version, please look forward for this in a later version.

Author Tag Cloud

Creates a template tag to create an author specific tag cloud and creates a new permalink structure to drill down into content by author and tag.

Keith S.

The best new feature in WordPress 2.3 is the integration of tagging into the core of WordPress. However, the tag cloud widget & functions that are included leaves a lot to be desired. So, with time on my hands, I decided to whip up my own version of the tag cloud that lets you configure the tag cloud with all the customizations (well, almost, see below) the tag cloud template tag allows.
You can find the plugin home page (and leave comments) <a href="http://keithsolomon.net/ctc/" rel="nofollow ugc">here</a>.
<h3>NOTE</h3>
Development on this plugin has STOPPED! I am looking for someone to take it over. Find more info <a href="http://wp.me/p4xrG-7q" rel="nofollow ugc">here</a>
<h3>Upgrade</h3>
I suggest using the built-in WordPress plugin update feature, but to manually upgrade, follow these instructions: 
1. Deactivate the plugin in the WordPress admin menu. 
2. Delete the existing <code>tag-cloud.php</code> file from the <code>/wp-content/plugins</code> folder. 
3. Upload the <code>tag_cloud</code> folder to the <code>/wp-content/plugins/</code> directory. 
4. Activate <code>Configurable Tag Cloud</code> through the ‘Plugins’ menu in WordPress and add the widget to your sidebar. 
5. (Optional) Add <code>ctc()</code> template tag to your theme. Can be configured either via the Options menu, or via parameters in the template tag.

Configurable Tag Cloud (CTC)

Display a tag cloud customized with your preferences in the sidebar.

Author Tag Cloud vs Configurable Tag Cloud (CTC)