Epigrade

Add page title, meta description, keywords and robots to all post types and taxonomies. 
Plugin will automatically change page titles for posts, pages, custom posts, categories, tags and custom taxonomies to 
whatever you have entered. Also will inject meta fields in template head section. If however you leave fields empty 
default WordPress or theme behaviour will occur. 
This plugin also removes taxonomy description column from listing table.
You can use it in your theme or other plugin. It creates the following taxonomy and post meta fields: 
 _page_title, <code>_meta_description</code>, <code>_meta_keywords</code>, <code>_meta_robots</code>.
Example usage:
<pre><code>// Get page title value for taxonomy with ID $term_id:
$taxonomy_title = get_term_meta( $term_id, '_page_title', true );

// Get page title value for post with ID $post->ID:
$post_title = get_post_meta( $post->ID, '_page_title', true );
</code></pre>

WP Simple SEO Meta

Add page title, meta description, keywords and robots to all post types and taxonomies.

Stefan

Ever noticed that on tag-pages multiple tags are possible? E.g. if you want to show all 
posts having “tag1” AND “tag2”, just go to 
http://yourwordpressblog/tag/tag1+tag2
But only “tag1” is correctly displayed (see screenshots). 
With this plugin you can use more than one tag correctly. This is especially interesting if 
you want to optimize some key phrases (like “tag1 tag2”) for searchengines.
Moreover this plugin can add the description of the tags to your tag-pages, simply put
<pre><code><?php echo multi_tags_get_description('', ''); ?>
</code></pre>
into your theme-file “tag.php”. 
To display the correct tags, just replace the call to
<pre><code>single_tag_title( '', false ) 
</code></pre>
with
<pre><code>if (function_exists('multi_tags_get_title'))
 echo multi_tags_get_title('and', 'or')
else
 single_tag_title( '', false )
</code></pre>
The inclusion of your tags into “meta keywords” resp. the inclusion of the tag-descriptions 
in “meta description” is done by the plugin. 
Simply check the corresponding checkboxes in the MultiTags-setting-page.
For more examples and background information have a look at:
http://www.vogel-nest.de/wp_multitags_plugin
<h3>Thanks</h3>
To Frank Bueltge http://bueltge.de for motivation and checking the first draft.

MultiTags

Display correct tags when calling a tag-page with more than one tag.

WP Simple SEO Meta vs MultiTags