Merchant Center is a service that allows sellers to show more extensive information in ads about their stores and products on Google Shopping, as well as other Google services. With this service in the ad, you can show not only text, but also the image of the product, its name, price and share, as well as the URL of your site. Google announced several new tools in the Merchant Center: additional feeds and the “Optimization” section. The information about them is published in the blog of AdWords.
Merchant Center accounts now have two kinds of feeds: primary and secondary. The main feed is a data source that is mandatory for displaying ads with your products.
Additional feeds are needed in order to change the data about the products entered in the main feed (but not to delete or add products). With the help of additional feeds, you can add special custom labels or promotion id to the products in the main feed, and also replace the attribute values. Using one additional feed, you can change several basic ones.
This novelty will first appear in accounts created after July 13, 2017, and in October and in all others.
On the new tab “Optimization” will appear cards with suggestions for improving feeds and campaigns. The information appears on it as soon as enough data is collected in the account. 
Feed Rules became available in the Content API. At the same time, advertisers were able to update products without changing the feed directly. For example, they can apply custom labels based on other values, assign a delivery cost depending on the weight of the goods, add brand advantages to the beginning of the title attribute.
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