text messaging. One research system that certainly goes beyond basic text messaging is The Mad Hatter’s Cocktail Party (Aoki et al., 2003). Designed for an era of near continual presence, this system targets the audio component of group-based mobile communication by simulating the natural “cocktail party effect” whereby people attend to a conversation among a smaller group in the midst of a larger social context. In a group conversation on mobile devices, The Mad Hatter’s Cocktail Party system automatically detects who people are talking to and attenuates the volume on the remaining conversation members. Although the Slam system described here is focused on text and photo communications, it is analogous in the attempt to build into mobile devices support for naturally occurring social processes, with The Mad Hatter’s Cocktail Party mimicking natural group conversation dynamics and the Slam system mimicking group membership dynamics (see Slam User Experience below).
Beyond UPOC the few commercially available options for group messaging generally are limited to adding multiple recipients to email or text messages. This presents a variety of issues, such as lack of user interface for group management and time consuming nature of typing in multiple recipients to an email from a mobile device, that hinder research on this form of mobile device-based computer mediated communication. Many of these issues were addressed nicely in the QuickML system (Masui and Takabayashi, 2003) that supported the creation of distribution lists simply by sending an email to the system. Once distribution lists are created, distribution list members can be added by sending mail to the list and putting new members on the Cc line. Although not exclusively designed for mobile devices, approximately 45% of QuickML usage is from mobile devices, highlighting the benefit of simple group management, persisted conversation groups, and wider distribution of content to the mobile device user. Similarly the system presented here supports simple group creation and distribution list-like messaging, although rather than email, the Slam system uses either HTTP for internet connected devices and SMS for all other devices. As described in further detail below, the Slam system also provides a rich user interface and additional features such as personal profiles.
Group-based mobile messaging, then, should support the social side of leisure by increasing communication between group members, particularly around daily life and day-to-day activities. In turn, this should strengthen social relationships amongst group members. To test for these effects, an experimental system for group-based text and photo messaging was developed for the Windows Smartphone. Figure 1 shows the Slam application home screen. The four photo tiles at the top left serve as entry points to the text and photo-based conversation for the four most recently active groups. These photo tiles also show the most recently shared photo for these groups in order to give a sense of recent member activity at the top level of the