Google announced the beta release of Review Extension in June, a feature that allowed advertisers to add an endorsement quote from a reputable publication into their AdWords ads. The feature is now being officially rolled out to all the AdWords accounts.
Advertisers will be able to find Review Extension option in the Ad extensions tab in their AdWords account in the coming days. A paraphrased review or an exact quote from a publication can be included in the ad. However, it might take a few days to get the Review Extensions approved.
For better exposure and greater flexibility, Google recommends advertisers to set one Review Extension at campaign level. Although, submission of more than one review is allowed but the one approved will only be run in the ad. Google will be giving higher priority to campaign level extensions than ad group level extension, so they will get reviewed quickly.
It is however important for your review to focus on business as a whole than on a specific product or service. The Review Extensions will be displayed along with other extensions, except the offer extensions.Google Starts Rolling Out AdWords Third-Party Review Extension to All Accounts!,