Existing research into user engagement with public displays tends to focus on aspects of visual and interaction design, with less thought given towards how the choice of content may influence user behavior. In this article, we survey the existing literature, particularly deployment studies of public displays, for lessons learned on the ramifications of content with different properties. We find that local and timely relevance of content, as well as user-driven content creation, have been independently shown to foster user engagement, but that few other solid conclusions can be drawn from the literature. On the whole, the aspect of content tends to be underspecified and not fully reflected in studies of public displays.