Google recommends that website owners start to provide special XML code snippets to assist it in sorting and categorizing their website data. This is called structured data and is usually done in a format known as microdata.
This new format is not hard to understand nor is it hard to implement, but it is important to know that Google considers its use important and is making it fairly simple for website owners to add these code snippets.
First, not all data on your website can be marked up as structured data. For now Google is only using code for products, local businesses – including address, phone, and other information, articles, software applications, reviews, events, and movies. Each year Google has added new categories as they expand the types of data that they are integrating into search results.
Use of special tags:
Coding a review will need special tags that denote rating, vcard, title, name, locality, and region. This is all a part of sorting the data for Google in their approved and specific format. Google makes it pretty easy for website owners to start using structured data and has even provided some great online tools.
Here are a few additional resources for you to consider:
Google’s blog post on the topic:
http://googlewebmastercentral.blogspot.com/2013/05/getting-started-with-structured-data.html
Structured Data Markup Helper:
https://www.google.com/webmasters/markup-helper/
Embedding Structured Data for Gmail:
https://developers.google.com/gmail/actions/embedding-schemas-in-emails
Google Webmaster Tools Data Highligher:
https://www.google.com/webmasters/tools/home?hl=en
Structured Data Bread Crumb Snippet: