Philipp Speck

This plugin will give you the ability to use the <code>excerpt</code> as <code>meta description</code> for any post or page. From now you are able to control the description of your site which will be displayed on the search engine results pages. 
By activation the plugin enables the excerpt for static edit pages in admin area.
Related Links
<ul>
<li><a href="http://www.typomedia.org/wordpress/plugins/wordpress-meta-description/" title="Homepage of WordPress Meta Description" rel="nofollow ugc">Homepage</a></li>
<li><a href="https://wordpress.org/extend/plugins/wordpress-meta-description/changelog/" title="Changelog for WordPress Meta Description" rel="ugc">Changelog</a></li>
<li><a href="https://wordpress.org/extend/plugins/wordpress-meta-description/faq/" title="FAQ for WordPress Meta Description" rel="ugc">Questions</a></li>
<li><a href="http://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=35264#1" title="Create good meta descriptions" rel="nofollow ugc">Information</a></li>
</ul>
Note: 
Before installing or upgrading new plugins, please backup your database first!

WordPress Meta Description

With this plugin you can control the text which will be shown as description on the search engine results pages.

This plugin will make it possible to use tags as <code>meta keywords</code>. Under <code>Pages</code> you will find a new meta box called <code>Keywords</code>. 
By activation the plugin registrates a separate taxonomy which is independent from post tags. 
Today’s search engines don’t use <code>meta keywords</code> as a criteria at all, but who knows for what they will be good in future 😉 
For me tagging is necessary to bring pages in relation and gives me the possibility to save my tags redundant in the database.
Features
<ul>
<li>Use post tags as <code>meta keywords</code></li>
<li>Registrates own <code>taxnomy</code> for pages</li>
<li>No coding needed</li>
<li>Language support</li>
</ul>
Related Links
<ul>
<li><a href="http://www.typomedia.org/wordpress/plugins/wordpress-meta-keywords/" title="Homepage of WordPress Meta Keywords" rel="nofollow ugc">Homepage</a></li>
<li><a href="https://wordpress.org/extend/plugins/wordpress-meta-keywords/changelog/" title="Changelog for WordPress Meta Keywords" rel="ugc">Changelog</a></li>
<li><a href="https://wordpress.org/extend/plugins/wordpress-meta-keywords/faq/" title="FAQ for WordPress Meta Keywords" rel="ugc">Questions</a></li>
</ul>
Localization
<ul>
<li>German translation by <a href="http://www.destio.de/" title="Designstudio, Philipp Speck" rel="nofollow ugc">Designstudio, Philipp Speck</a></li>
<li>Slovak translation by Branco Radenovich</li>
</ul>
Note: 
Before installing or upgrading new plugins, please backup your database first!

WordPress Meta Keywords

This plugin gives you the ability to set Meta Keywords in WordPress. Under pages it will registrate a separate taxonomy for keywords.

WordPress Meta Description vs WordPress Meta Keywords