About Rich Snippets
Rich snippets are search results that have been enhanced using structured data from your webpages, which we've found are useful for users who are shopping. This feature has been launched for shopping sites, and the new format shows price, availability, and product reviews on pages offering a product for sale.
If you're a merchant, you can give Google detailed product information we can use to display rich snippets right on our search results pages. The Products and Shopping article gives you an overview of how rich snippets work with your Google Shopping listings.
Submitting Rich Snippets information via Google Merchant Center
To submit your product ratings: Review data can be submitted using markup based rich snippets. Please refer to the reviews article to learn more about markup-based rich snippets
To submit product status: Stock status may be submitted through the availability and price attribute. Read about them on our feed specification.
Please visit the Webmaster Tools Help Center to learn more about rich snippets.