Schema is the site that gives developers the proper code to display Rich Snippets. Rich Snippets are Google search results that stand out from the rest. Microdata is the type of code used to display Rich Snippets.
Structured Data is a group term used to describe the various types of languages specifically created to help search engines understand web pages better—Microdata is just one of a few.
- Structured Data Testing Tool by Google
- Schema.org – embed structured data to web pages for use by search engines.
- Rich snippets “Apple Pie” example
- Schema Creator – generate and manually add Microdata to your site
- Schema Creator for WordPress – dynamically add Microdata to your website
Note: There’s no guarantee that Google will display a rich snippet for your search result, and the rich snippet validator can be buggy at times.