Structured data (also called "semantic data", "rich snakes" and "Schematic org") is about data / information / markup that tells search engines what the content shown in the search results is about.
Technical terms look like this gives most opinion through the use of examples, so let's see how structured data looks like in practice:
Structured data is all about highlighting the display pieces of information for a page in search results. For a shoe, the model will be nearby to highlight photos of shoes, as well as price, colors and stock status.
For food recipes, it is relevant to highlight the "bite" for preparation time, image and stars (reviews).
It's easy to see why the word "rich snouts" is one of the many names on this: your page in search results seems to be more enriched and with information that goes beyond standard text elements.
Why use structured data? Search engines are as familiar quite despair of how their algorithms different elements on a weights given website, and much seem to use structured data is not a direct the ranking factor. But we know that a page that has good and relevant data is highlighted in its results will get more clicks than a similar page that has not implemented this. There is also great unity in the SEO environment as structured data will be much more important in the future.
Structured data provides an opportunity to show important content to the user before visiting the page, and since most websites today do not use this one will dominate and stand more in search results than your competitors.
Google Shopping is a feature of Google search has expanded extensively in recent years. Several experts in e-commerce predict that in a few years we will make a lot of purchases through the Google Shopping interface without going to the online store. Here we have the opportunity to filter by size, price, colors and types and Google Shopping returns products from online stores that offer products that match our needs.
Structured data that contains different attributes will be a prerequisite for products to be downloaded in this interface. If many of your online purchases are outside of the online store like in an advanced version of Google Shopping, go as an e-commerce player to miss amazing opportunities by not arranging their structured data.
How? Structured data (Schema.org) is not automatically flagged by Google. It is a form of "vocabulary" with the corresponding tags that are added to the HTML. In familiar style, Google has good guidelines and associated testing tools to help you properly implement structured data: