The WP Social SEO Pro plugin comes in 2 Versions. There is a Lite (Free) Version which be downloaded here and there is the Pro Version which has a series of advanced features and capabilities which go beyond the Lite Version of the plugin. The WP Social SEO Pro plugin allows you to enhance and magnify the Social Media Signals and SEO transmitted from your Wordpress Blog to Social Networks like Facebook, Twitter, and Google Plus; along with easily configuring Google Authorship and Publisher status for you and other users of your Wordpress blog. It also enables the full use of Google Structured Data (Rich Snippets) on your blog, Image Optimization via the Kraken API, HTML5 Boilerplate Optimization of your .htaccess file, and more.
The SEO Booster Lite (Free) Version is limited to Posts on your Wordpress blog and does not have the advanced Google Plus and Advanced Twitter Card Optimizations as well as a host of smaller fine tuned optimizations not readily apparent from the outside looking in.
The power of the SEO Pro and SEO Pro Pro Plugins is the behind the scenes Meta Tagging, Rich Snippet, and Authorship/ Publisher attributes which allow Google, Bing, Facebook, Twitter, Google Plus, and other search engines and Social Networks identify and deliver content from your site in Search and through Social Sharing more effectively than you would be able to do otherwise.
The SEO Pro plugin integrates with both the Wordpress SEO Plugin from Yoast and the All in One SEO Pack Plugin. While both these SEO Plugins are great and do have some basic Social features, the SEO Pro plugin takes these basic settings and transforms them into advanced and customized SEO and Social options you can use on each and ever page and post on your site (Pro Version, Free Version is limited to Posts only). We highly recommend the Wordpress SEO Plugin as the single best SEO Plugin for your blog. While very capable, the All in One SEO Pack plugin requires payment for advanced features which the Wordpress SEO Plugin from Yoast has included already and Yoast's plugin is completely Free. Plus, in our testing, the All in One SEO Plugin still did not have all the features or deliver the SEO results which were provided by the much more powerful Wordpress SEO Plugin.