Kurzzusammenfassung
In this paper, we describe a novel approach to the privacy problem that photos showing persons are often "meddle-shared" by others online. We introduce a set of four elementary privacy preferences a photo subject can have. These preferences are represented by corresponding symbols - "Offlinetags" - which can be worn in the form of stickers or badges and which are designed to be easily recognizable by humans and algorithms. Especially for the context of public events, these Offlinetags can serve as a basis for novel practices of photo sharing that respect the photo subjects' privacy preferences.