williamlong

The Keyword keyword plugin replace the sensitive keyword in the post content. Keyword filter plugin works by creating a WordPress filter for the post contents. When the post get displayed, WordPress gives the post content to the keyword filter plugin and the plugin returns some modified content. Replace the sensitive keyword with specific keyword.
The WordPress keyword plugin support Far East Characters (such as Chinese Characters). You may also create your own keyword filter lists as needed.

Keyword Filter

Keyword Filter Plugin Replace the sensitive keyword with specific keyword in the post content.

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.

Keyword Filter vs wp-markKeyword