We call these shared endorsements. Here's what you need to know:
You're in control: Your content is only shared when you choose, and shared endorsements don't impact who can see your content or activity.
To help your friends and others find cool stuff online, your activity (such as reviews, +1s, follows, shares, etc.) may be used along with your name and photo in commercial or other promotional contexts.
Setting: Shared Endorsements in Ads
This setting below allows you to limit the use of your name and photo in shared endorsements in ads. It applies only to actions that Google displays within ads; the "Summertime Spas" example above shows a shared endorsement appearing in an ad on Google Search. Changing this setting does not impact how your name and photo might look in a shared endorsement that is not in an ad — for example, when you share a music recommendation that is displayed in the Play Store. You can limit the visibility of activity outside of ads by deleting the activity or changing its visibility settings.