Joseph Hinson

Do you have a lot of categories and are sick of having a huge list in your sidebar? Want to highlight only a few of them to make your site easier to navigate?
While redesigning WordPress sites for our clients we kept running into this problem over and over. They had a huge list of legacy categories but only wanted to highlight a few of them. We wrote this plugin to allow them to select which categories to show and which categories to initially hide.
All categories are still accessible by a “see all” link at the bottom of the list.
Add the widget to your sidebar to make it live.

Category Expander

Allows WordPress Admins to show only a selected few categories on the sidebar and hide the rest from view until visitor clicks "See All".

reneade

This wordpress plugin provides a configurable tagcloud that shows tags depending of the current context only. For example the tagcloud shows only tags that really occur in the current category, or within the current date-, author-, tag- archive or even only the tags that occur in the search results. 
It is also possible to restrict the links of the tag cloud to the current viewing tag archive or category: If you click on the tag “test1” within the tag cloud of the tag archive of “test2” the target page will only contain posts that have both tags, like a drill down navigation. It is possible to exclude the tag of the tag-archive itself from the tagcloud. 
For the single post pages you can configure the tagcloud to show also related tags of the current posts, not only the direct tags of the post. And you can configure the tagcloud to exclude the tag of the current post, to show only the related tags. 
The style and sizes of the tagcloud can be configured, and the widget can be configured to be only visible if viewing a tag archive, category, a sinlge post or even only if viewing the searchresults for example. It is also possible to configure the number of tags that should be displayed in the different conditions.
Plugin Website: http://www.rene-ade.de/inhalte/wordpress-plugin-sensitivetagcloud.html 
Donations: http://www.rene-ade.de/stichwoerter/spenden
<h3>Update</h3>
<ol>
<li>Deactivate the Plugin</li>
<li>Remove the existing folder ‘sensitive-tag-cloud’ with all files from the ‘wp-content/plugins’ folder on your webserver</li>
<li>Upload the new folder ‘sensitive-tag-cloud’ with all files to ‘/wp-content/plugins’ on your webserver</li>
<li>Activate the plugin through the ‘Plugins’ menu in WordPress</li>
</ol>

SensitiveTagCloud

This wordpress plugin provides a tagcloud that shows tags depending of the current context (e.g. Category, Author, Tag, Post) only.

Category Expander vs SensitiveTagCloud