Microformats are semantic markup systems that “tag” your content (post/photo/video) in the context of related knowledge. Examples are hCard (contact details) and hRecipe (food recipes).
Microformats help people and machines understand what your content is “about”. This metadata helps search engines and humans to better understand your message in the context of related information.
Emily Lewis explains the importance of microformats and demonstrates how easy it is to implement them. Web designers, bloggers, and entrepreneuers can benefit from understanding and implementing microformats in their web apps and content management systems. Buy Emily’s book: Microformats Made Simple