Designing for Ecosystems of Communication Apps

More and more, people communicate via not one, but a complex mix of apps. In particular, couples, close friends and families use multiple apps to express caring in diverse ways throughout the day. This calls for a new focus of study: besides observing how each app shapes communication, I argue that we need a deeper understanding of how people communicate via ecosystems of communication apps. In Part One, I show that users' communication practices in one app are not only influenced by its contacts and features but also by the contacts and features in their other apps. A first study shows that the contacts in an app affect the conversations with other contacts. To control this phenomenon, people isolate contacts in different apps: they create communication places, each with its own membership rules, perceived purpose, and emotional connotations. As relationships change, people move contacts in and out of their apps, driving communication places to redefine each other. People may break their places by bringing outsiders when the functionality they need exists only in one app.A second study shows that people customize their communication apps to better express their identities, culture and intimate bonds with others. Beyond customizations, the features of each app nurture expression habits that transfer to other apps, thus influencing how users express themselves across their entire app ecosystem. App-exclusive features prevent consistent identity expressions across apps and interfere with relationship-specific communication styles. Based on these insights, I propose four design directions for supporting ecosystems of communication apps: allow multiple communication places within the same app, support relationships across apps, provide access to functionality from other apps, and enable user-owned---rather than app-exclusive---communication tools. In Part Two, I explore those design directions by repurposing three mechanisms currently available in mobile operating systems: notifications, which users can overlay on top of any open app; gesture commands, which users could perform on any app that recognizes gestures; and soft keyboards, which appear in any app that accepts text input. I repurpose notifications as peripheral awareness displays to build Lifelines, a dedicated communication channel for couples which shares visual timelines of contextual information, e.g. closeness to home, battery level, and steps. A longitudinal study with nine couples shows how each couple leveraged Lifelines in unique ways, finding opportunities for coordinating implicitly, starting conversations, and being more understanding with each other. I repurpose gesture commands as personal gesture shortcuts to diverse functionality which users can perform in any app. I present a design envisionment and study user strategies for creating personal gestures in a comparative study of Fieldward and Pathward, two interaction techniques for creating gestures that are easy to remember and easy for the system to recognize. The results show large individual differences in users' gesture-creation strategies, reflecting their culture, their intimate bonds with special contacts and technology usage habits. Last, I repurpose soft keyboards as communication toolboxes that users can carry with them from app to app. I present a design envisionment and explore its feasibility by building two prototypes: The Shared Emoji Toolbox, which allows sharing collections of emoji shortcuts, and Command Board, which combines gesture typing with gesture shortcuts to access rich sets of commands. In conclusion, I argue that when people communicate via multiple apps, each app shapes how communication happens in others. We should shift from building isolated apps to designing mechanisms that help users preserve their communication places and express their identities and intimate bonds with others consistently across their apps.