Searching for online health information has been well studied in web search, but social media, such as public microblogging services, are well known for different types of tacit information: personal experience and shared information. Finding useful information in public microblogging platforms is an on-going hard problem and so to begin to develop a better model of what health information can be found, Twitter posts using the word "depression" were examined as a case study of a search for a prevalent mental health issue. 13,279 public tweets were analysed using a mixed methods approach and compared to a general sample of tweets. First, a linguistic analysis suggested that tweets mentioning depression were typically anxious but not angry, and were less likely to be in the first person, indicating that most were not from individuals discussing their own depression. Second, to understand what types of tweets can be found, an inductive thematic analysis revealed three major themes: 1) disseminating information or link of information, 2) self-disclosing, and 3) the sharing of overall opinion; each had significantly different linguistic patterns. We conclude with a discussion of how different types of posts about mental health may be retrieved from public social media like Twitter.

Visual markers, in particular QR codes, have become widely adopted in museums to enable low cost interactive applications. However, visitors often do not engage with them. In this paper we explore the application of visual makers that can be designed to be meaningful and that can be created by visitors themselves. We study both the use of these markers as labels for portraits that link to audio recordings and as a mechanism for visitors to contribute their own reflections to the exhibition by drawing a marker and linking an audio comment. Our findings show visitors appreciated the use of the aesthetic markers and engaged with them at three levels -physical placement, aesthetic content and digital content. We suggest that these different levels need to be considered in the design of future visiting systems, which make use of such markers, to ensure they are mutually supporting in shaping the experience.

We propose a novel approach, which involves visitors physically manipulating visual representations of artefacts and scanning with their mobile phone different groups or sequences of items in order to reveal digital information about their relationships. To explore this interaction mechanism we collaborated with a museum to develop an interactive paper map, on which visitors can place tangible representations of artefacts and scan the resulting arrangements. Based on an in-situ study of its use, we reveal that museum visitors engaged in different strategies for exploration of relationships between artefacts in the museum collection (inspection, strategic and experimental configuration), and for social collaboration (sharing the interaction space, adopting interaction roles and sharing a reaction to the "reveal"). We discuss how future interactive installations can accommodate these behaviors.

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