Google is facing a privacy backlash after revealing plans to use pictures of Google+ users in online advertisements - without their permission.
The Internet giant says that from November 11 it may publish usernames, profile photographs, reviews and ratings in what it is calling "shared endorsements".
The idea is to give online adverts a "social" context, making them less annoying and more engaging for Internet users suspicious of commercial marketing.
Users who like a song in the Google Play store or rate a favourite restaurant could find their approvals harvested and published as official recommendations.
Google's plans are similar to shared endorsements currently used by Facebook, which faced legal action over the practise in 2011. It ended up paying $20m (£12.49m) in damages to users whose pictures it had used without permission.
In a statement on its website Google said: "To ensure that your recommendations reach the people you care about, Google sometimes displays your reviews, recommendations and other relevant activity throughout its products and services.
"This sometimes includes shopping contexts, like Google Music play store and ads. Your profile name and photo may appear with the recommendation".
Users will be able to opt out of the plans but privacy campaigners are concerned many people could be unaware they have already been opted in without their consent.
