A search engine sees this: Oranges are healthy.
The search engine won’t know if you’re talking about: orange, the fruit, orange, the color, or Orange, the band. In order to properly promote a website, search engines require that you be more specific with your content. This is where microdata comes in. When you include microdata (code that specifies your article) into your headline and your information, the search engine will now know you are talking about fruit and can promote your content to anyone who is looking for that specific content.