Tag Posts Widget is a light widget to show posts from a given set of tag.
Ispired by Category Posts Widget by James Lao – http://jameslao.com
Features:
<ul>
<li>Select any number of tag to be shown.</li>
<li>Add the tag browsed, while browsing the tag archives.</li>
<li>Set how many posts to show.</li>
<li>Option to append the tag names to the title.</li>
<li>Multiple widgets.</li>
</ul>

Tag Posts Widget

Adds a widget that shows the post from a given set of tags.

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.

Tag Posts Widget vs SensitiveTagCloud