As discussed previously structured data is a way to markup your website. Google will crawl your website and possibly change this microdata into Rich Snippets. The snippets the few lines of text that appear under every search result—are designed to give users a sense for what’s on the page and why it’s relevant to their query.
Google supports rich snippets for the following types of content: reviews, businesses and organizations, people, products, recipes, events and music. Google has indicated that they are trying to add more rich snippets into their search results. However, please not that just because you markup your website does not mean Google has to include your markup into its search results.