Matthew Poer

We’ve created a WordPress Plugin which adds site-wide Keyword and Description meta-tags. We’re using it on this web site!
The process is simple: define some site-wide description and keyword meta-tags. These will be used everywhere unless you (or your authors) choose to append keywords or override them completely for a particular post or page.

PSI Meta Tags

Add Meta-Tags to your site, and customize them on a post-by-post basis

conis

This plugin can high light keyword after someone searchecd it, which supports the search engines like google, baidu, ask, yahoo&bing. 
1.the highlight words are from the link of the search engine 
2.every key word is added with a link, clicking the link can search in the site 
3.on the top of the article show the key words which users are searching 
4.high light the searching result 
5.the highlight words are showed in the content and the excerpt
more information, pls visit(English):<a href="http://conis.cn/1365/" rel="nofollow ugc">http://conis.cn/1365/</a> 
国内的朋友请访问我的博客获取更的信息 <a href="http://conis.cn/1344/" rel="nofollow ugc">http://conis.cn/1344/</a>

wp-markKeyword

This plugin can high light keyword after someone searchecd it, which supports the search engines like google, baidu, ask, yahoo&bing.

PSI Meta Tags vs wp-markKeyword