posting a picture and marking it as only viewable by friends, but tagging someone else as appearing in that picture, causes the post to be viewable by friends of the tagged person(s). Photos taken of people by others can be posted on Facebook without the knowledge or consent of people appearing in the image; persons may have multiple photos which feature them on Facebook without being aware of it. A study has suggested that a photo of a person which reflects poorly on them posted online can have a more harmful effect than losing a password. When commenting on a private post, the commenting user is not informed if the post they commented on is later made public – which would make their comment on said post also publicly viewable. Quit Facebook Day Quit Facebook Day was an online event which took place on May 31, 2010 (coinciding with Memorial Day), in which Facebook users stated that they would quit the social network due to privacy concerns. It was estimated that 2% of Facebook users coming from the United States would delete their accounts. However, only 33,000 (roughly 0.0066% of its roughly 500 million members at the time) users quit the site. The number one reason for users to quit Facebook was privacy concerns (48%), being followed by a general dissatisfaction with Facebook (14%), negative aspects regarding Facebook friends (13%), and the feeling of getting addicted to Facebook (6%). Facebook quitters were found to be more concerned about privacy, more addicted to the Internet, and more conscientious. Photo recognition and face tagging Facebook enabled an automatic facial recognition feature in June 2011, called "Tag Suggestions", a product of a research project named "DeepFace". The feature compares newly uploaded photographs to those of the uploader's Facebook friends, to suggest photo tags. National Journal Daily claims "Facebook is facing new scrutiny over its decision to automatically turn on a new facial recognition feature aimed at helping users identify their friends in photos". Facebook has defended the feature, saying users can disable it. Facebook introduced the feature on an opt-out basis. European Union data-protection regulators said they would investigate the feature to see if it violated privacy rules. Naomi Lachance stated in a web blog for NPR, All Tech Considered, that Facebook's facial recognition is right 98% of the time compared to the FBI's 85% out of 50 people. However, the accuracy of