Google Merchant Centre allows you to publish your store and product information online making it easy for customers to find out all about you when they search online. Without setting up your Google Merchant Centre, you cannot run Google Shopping Ads. Merchants will be required to fill out their product category, Product name, Attributes, pictures and Inventory (optional) in the Google Merchant Center. Usually, you will need to implement Schema Markup for this. You can even detail Product promotions in Google Merchant Centre. Google Merchant Centre and Google Shopping Network are related but they are not the same thing. You can think of Google Merchant Centre as a platform through which a merchant uploads and shares product information into the Google ecosystem. Whereas Google Shopping is a search service for users to search for products and compare prices online. Though they both relate to shopping they serve slightly different purposes.