Google has announced an update to its terms of service that outlines how it might use your content in advertisements across its network.
For those with a Google Account, a +1 you give or review you write might be used alongside an advertisement for the business you endorsed.
"The +1 you gave your favorite local bakery could be included in an ad that the bakery runs through Google," the company said.
The ads have been dubbed shared endorsements, and will only be displayed to people in your social circle, or those with whom you've opted to share information like +1s and reviews. If you don't want Google using your information, you can opt out by navigating to the shared endorsement setting, unchecking the box at the bottom, and clicking "Save."
The setting will be on by default, but if you previously told Google that you did not want your +1's to appear in ads, then "of course we'll continue to respect that choice as a part of this updated setting," Google said.
Google made the change to the "Your Content in our Services" section of its terms of service.
The new text reads: "If you have a Google Account, we may display your Profile name, Profile photo, and actions you take on Google or on third-party applications connected to your Google Account (such as +1's, reviews you write and comments you post) in our Services, including displaying in ads and other commercial contexts. We will respect the choices you make to limit sharing or visibility settings in your Google Account. For example, you can choose your settings so your name and photo do not appear in an ad."
Meanwhile, Google will also display your +1s or reviews in non-ad content. If you gave a four star review to a band's album on Google Play, for example, your friend might see that review displayed when he navigates to the band's Google Play page. There's no way to opt out of this.
Facebook landed in hot water when it used members' content in advertisements via a programme known as "Sponsored Stories." Users who were unaware that they were basically being used as unpaid spokespeople sued Facebook, which was eventually required to hand over $20 million (£12.5m) in a settlement.
Google's terms of service update, meanwhile, also included sections warning people to use their mobile devices safely (translation: don't text and drive), as well as warnings about password safety.