Facebook has come under fire for quietly expanding the availability of technology to automatically identify people in photos, renewing concerns about its privacy practices.
The feature, which the giant social network automatically enabled for its more than 500 million users, has been expanded from the US to "most countries", Facebook said on its official blog on Tuesday.
Marc Rotenberg, president of the non-profit privacy advocacy group Electronic Privacy Information Center, said the system raised questions about which personally identifiable information, such as email addresses, would become associated with the photos in Facebook's database.
He also criticised Facebook's decision to automatically enable the facial-recognition technology for its users.
"I'm not sure that's the setting that people would want to choose. A better option would be to let people opt-in," he said.