Facebook is shutting down the photo tagging facial recognition program that was key to its product for years, and is deleting more than a billion "face prints" of users, according to a blog the company posted Tuesday. 

"We're shutting down the Face Recognition system on Facebook," said Jerome Pesenti, vp of artificial intelligence at Facebook. "As part of this change, people who have opted in to our Face Recognition setting will no longer be automatically recognized in photos and videos, and we will delete the facial recognition template used to identify them."