AndrewUlrich

<p>This plugin creates two widgets:</p>
<ol>
<li>A widget where you can choose from all the categories in your blog.</li>
</ol>
<p>This is similar to what newegg.com uses, where you can select multiple categories, and it will only show posts belonging to all the categories you select, and such categories can be narrowed down by selecting their subcategories.</p>
<ol>
<li>A widget where you can choose from all the tags in your blog</li>
</ol>
<p>You can select the tags you want to search for, and it will only show posts that have all of the tags you selected.</p>
<h3>Known Issues</h3>
<p>After upgrading from 2.1 to 2.2 it is highly recommended that you deactivate the plugin and then re-activate it.  Unfortunately WordPress 3.1 no longer calls register_activation_hook when the plugins are upgraded, so this may be necessary, otherwise you may not see all your categories.</p>
<p>When using version 3.2 or above, and excluding categories, the display order may or may not be mixed up when you exclude a parent category.</p>


Faceted Search

This plugin will create widgets that you can use to conduct faceted searches using the categories or tags on your site.

whiletrue

<p>“Categorized Tag Cloud” is a free plugin for WordPress, developed by the Whiletrue.it staff to generate a cloud with the website’s most used tags, in a sidebar widget.</p>
<p>The words inside the cloud are filtered by category, so you can better match your content by removing the unnecessary tag ids.</p>
<h4>Options</h4>
<p>The following options are customizable:</p>
<ul>
<li>category filters</li>
<li>number of tags shown</li>
<li>tag colors (fixed or random)</li>
<li>tag hover color</li>
<li>smallest and biggest font size</li>
</ul>
<h4>Reference</h4>
<p>For more informations:  <a href="https://www.whiletrue.it/categorized-tag-cloud-widget-wordpress/" title="www.whiletrue.it" rel="nofollow ugc">www.whiletrue.it</a></p>
<p>Do you like this plugin? Give a chance to our other works:</p>
<ul>
<li><a href="https://www.whiletrue.it/it/really-simple-share-wordpress-plugin/" title="Good Old Share" rel="nofollow ugc">Good Old Share</a></li>
<li><a href="https://www.whiletrue.it/most-and-least-read-posts-widget-for-wordpress/" title="Most and Least Read Posts" rel="nofollow ugc">Most and Least Read Posts</a></li>
<li><a href="https://www.whiletrue.it/reading-time-for-wordpress/" title="Reading Time" rel="nofollow ugc">Reading Time</a></li>
</ul>
<h4>Translators</h4>
<ul>
<li>Serbian translation by Ogi Djuraskovic ( firstsiteguide.com )</li>
</ul>


Categorized Tag Cloud

A cloud with the most used tags in a sidebar widget, filtered by post category.

Faceted Search vs Categorized Tag Cloud