Not used to improve search engine rankings, this is used to create a "rich snippet" in the search result, to entice users to click on the link.
From Anirvan Chatterjee's presentation at the VIVO conference:
Follow the directions at schema.org and schema.org/Person to add people-orientedHTML metadata to your profile pages.
Use www.google.com/webmasters/tools/richsnippets to test your syntax.
Make <meta name="description"> on profile pages readable and descriptive (e.g. "Jane Doe's profile, publications, research topics, and co-authors")
Create a dynamically-generated sitemap of all your profile pages (www.sitemaps.org)
Mention your sitemap in your robots.txt file, and then register it with Google Webmaster Tools.
Wait a day, user Google Webmaster Tools to validate that your sitemap works.