Introduction to Structured Data
Structured Data is on-page markup that helps search engines to better understand the information that is on your website. For example, if your website has news posts, you could use Structured Data to describe the properties for each news post, such as news content, the URL to the photo used on the post, comments, etc. Search engines use the information from your Structured Data to improve your search results listings.
Structured Data describes things on the web and their properties and has a high level of organisation. When data is structured and predictable, it is easier for search engines like Google to organise and display it in different creative ways. For example, the site profiles that you see for businesses on Google search results.
When Google makes their listings and site profiles, Structured Data is helpful as it is easier for Google to find the relevant information about your business. Site profiles can also be done by just creating a Google Plus page. However, Google prefers to use Structured Data as more information can be found from this than from Google Plus alone.