With Google aiming to be the top review platform in every category, it is now also discouraging adding embedded reviews from non-Google sources.
Google’s John Mueller was asked if it would help with web rankings in Google to embed reviews from sites like Facebook, Bing, Yelp, etc., on your website and John stated bluntly that it would not. Google wishes to become the world’s top review platform and would not benefit from playing nice with other review sources. As such, Google is disincentivized from providing any ranking benefit to websites that promote third-party reviews. Mueller also warned against not using structured data on those third-party site reviews, making the benefits of including them non-existent if done correctly and a penalty if done poorly.