I have found some very useful plug-ins for WordPress. Both of these plug-ins help you optimize your blog for search engines.
The first is the Technorati tag plug-in. This allows you to tag your blogs with keywords that are linked back to Technorati. The use of this plug-in is invoked by using [tag] and [ /tag] surrounding your keywords separated by a comma. This allows readers to tag your post more easily.
The other plug-in that I use quite frequently is the title tag plug-in. Visit one of our blog posts and click on the title of the blog. You will notice that you are taken to a web page with that post on it. At the top of the blog is the actual title of the blog; however, in the title bar, is another title. This is the title that search engines see in the title tag of the web page. Titling my blogs something different using the title tag plug-in allows me to accomplish two things. One, it gives me the freedom to title the actual blog post anything I would like. Two, by putting keywords in the title tag I am optimizing my blog for those keywords.
I would love to hear of any more helpful plug-ins that you have found for WordPress.