If you read my previous post about the best SEO practices, I mentioned that one of the most important elements to search engine optimization is on-page (or on-site) optimization or, for the purpose of this post, the part of WordPress that deals with the “code”. WordPress is a great platform and takes care of about 80% of the mechanics of SEO according to Matt Cutts (Google Spam Chief). While this is true, it does not mean that you can’t improve it further and this is where the SEO plugins come into play. They help your site go that extra mile for added “technical optimizations”.
Note that there are many SEO plugins available out there, and you should always do some research for more information. The ones that I will be recommending here are all from credible sources (developers and on the WP repository), 100% free and tested. I use them either here or my other websites.