A Study on the Unawareness of Shared Photos in Social Network Services

Abstract—The habit of sharing huge amounts of photos on the social Web is creating many new privacy issues that have been addressed in a multitude of research efforts in the past few years. Most of this research focused on securing users ’ own photos and managing their online identity in terms of access control. However, implications for other people have not yet received sufficient attention. Photos affect the privacy of all depicted people and those mentioned in metadata. Therefore awareness about photos is a key issue for protecting privacy. While prior work studied only self-reported ratings, we quantify how aware people are of shared media. In the context of Facebook we show user-unawareness based on a study we conducted via an app combined with two supplementary questionnaires. We present data about 75 million photos and metadata as well as study results of 2254 participants. I