Passwords are the most common authentication scheme today. However, it is difficult for people to memorize strong passwords, such as random sequences of characters. Additionally, passwords do not provide protection against phishing attacks. This paper introduces WebTicket, a low cost, easy-to-use and reliable web account management system that uses "tickets", which are tokens that contain a two-dimensional barcode that can be printed or stored on smartphones. Users can log into accounts by presenting the barcodes to webcams connected to computers. Through two lab studies and one field study consisting of 59 participants in total, we found that WebTicket can provide reliable authentication and phishing resilience.

Current social media products such as Facebook and Twitter have not sufficiently addressed how to help users organize people and content streams across different areas of their lives. We conducted a qualitative design research study to explore how we might best leverage natural models of social organization to improve experiences of social media. We found that participants organize their social worlds based on life 'modes', i.e., family, work and social. They strategically use communication technologies to manage intimacy levels within these modes, and levels of permeability through the boundaries between these modes. Mobile communication in particular enabled participants to aggregate and share content dynamically across life modes. While exploring problems with managing their social media streams, people showed a strong need for focused sharing - the ability to share content only with appropriate audiences within certain areas of life.

When designing novel GUI controls, interaction designers are challenged by the "immaterial" materiality of the digital domain; they lack tools that effectively support a reflecting conversation with the material of software as they attempt to conceive, refine, and communicate their ideas. To investigate this situation, we conducted two participatory design workshops. In the first workshop, focused on conceiving, we observed that designers want to invent controls by exploring gestures, context, and examples. In the second workshop, on refining and communicating, designers proposed tools that could refine movement, document context through usage scenarios, and support the use of examples. In this workshop they struggled to effectively communicate their ideas for developers because their ideas had not been fully explored. In reflecting on this struggle, we began to see an opportunity for the output of a design tool to be a boundary object that would allow for an ongoing conversation between the design and the material of software, in which the developer acts as a mediator for software.