How is my site's data markup used by Google?

Structured data markup (also called microdata or rich snippets) is an HTML tag annotation that lets search engine crawlers and bots know that there is product data on your site and helps the systems reliably understand and process the data.

In the case of Google Shopping using, structured data markup can be used by Google in two types of cases:

• to check in an automated way, and therefore much faster, the consistency of your data between the feed exported in your Merchant Center account and the data present on your website.
  
  
• to automatically update, several times a day, the price and availability of your products on Google Shopping, if the option is enabled in your Merchant Center account.

  Indeed, if the price and availability of your products change very frequently (throughout a day for example) and that your product feed is not updated often enough, or if it takes time to be updated due to the volume of data, there may be inconsistency between the information in your feed and your product pages on your site. If Google notices this disparity, this may result in the suspension of your Google Merchant Center account.
  To solve this problem, and provided that your website is properly marked according to "shema.org" convention, you can enable the "item automatic update" in your Google Merchant Center account. Google will update the prices and availability of your items automatically, several times a day, by retrieving the information from your website.
  In the top right corner of your account interface, click on the "wheel" icon of the menu and then on "Automatic improvements". Activate the option "Enable Automatic item updates". If you want Google to update the prices AND availability of your products, select "Prices and availability". You also have the possibility to only ask the automatic update of prices OR availability. Remember to save:

  To have more info about benefits of automatic item updates, please read the Google official documentation.
  
  This feature (independant of the module) is useful but beware, it has its limits: if too many mismatches occur, automatic item updates will stop working and your account will be at risk for preemptive item disapproval. Learn more.
  Moreover, as mentionned above, if you want to take advantage of this feature, your PrestaShop website theme needs to correctly include these microdata according to the "schema.org" convention (tags that structure your data). If it doesn't, you will may receive warnings from Google about the non-compliance of your theme in structured data markup and the automatic item updates will not work (your data will simply be updated at the frequency indicated for your Merchant Center feed updating).