The source – support.google.com
Google Merchant Center launches automatic tagging for free product offers.
This feature, when used with third-party web analytics tools, allows you to understand how often clicks on free ads lead to purchases.
When a user clicks on a free offer, a special identifier is automatically added to the URL. The option helps:
- Track site conversions across all browsers for free offers, including local ones placed on the "Shopping" tab. Other types of conversions will not be taken into account.
- Generate separate reports on the effectiveness of free ads in other services, such as Google Analytics.
You can read more about this feature in the Help.