In June, Google announced the beta release of Review Extensions which allow advertisers to append a quote of endorsement from a reputable publication in their AdWords ads. Today, these Review Extensions will begin to roll out to all AdWords accounts.
You should see the Review Extensions option under the Ad extensions tab in your account within the next few days. The blurb you include in your ads can be a paraphrased review or an exact quote from the publication. Review Extensions can take a few days to be approved.
Google recommends setting one Review Extension at the campaign level for greater flexibility and exposure. You can submit more than one review, but only the first one to be approved will run. Also, campaign level extensions are given higher priority than ad group level extensions, so they are reviewed more quickly.
The review should focus on your business as a whole instead of a specific product or service — in the same way the starred reviews for ecommerce merchants are seller reviews rather than individual product endorsements.