Finally, how will the group context change the way mobile messaging is used to transition to face-to-face interactions? The increase in social communication might yield more face-to-face interactions. Group members who previously didn’t know each other as well, may feel more comfortable suggesting face-to-face get-togethers, or group members may realize through the messaging that they are physically close enough to one another that a spontaneous face-to-face meeting makes sense.
1.2 Mobile Photo Sharing
Photo sharing also plays an important role in the social side of leisure activities. It is a well documented medium for communicating experiences (Frohlich et al. 2002), and camera phones service such social goals as maintaining relationships and preserving group memory (Van House et al. 2005). Kindberg et al. (2005) stress the importance of common ground in these processes: because image sharing often includes few words, common ground between sender and receiver is critical for understanding the meaning of the media message. Given the additional recipients in group-based messaging, initially some group members might feel left out when they don’t understand the meaning of certain messages. However, the focus on images of everyday life we tend to see in photos from mobile devices (Makela at al. 2000) should help establish common ground. As common ground is established in group-wide messaging, or is already established in an existing social group, its effects reach multiple people simultaneously. Thus, one prediction for group-based mobile media sharing, particularly for known social groups, is an overall strengthening of the social bonds between group members.
Work on camera phone photo usage (Van House et al. 2005) and sharing (Davis et al. 2005; Counts and Fellheimer 2004; Markopoulos et al. 2004), suggests that it is not only an important medium for social connection, self-expression, and experience documentation, but that usage increases dramatically when barriers to sharing are reduced. Sharing camera phone photos with a group as easily as with an individual marks a dramatic reduction of the barriers to sharing, and we would thus expect a corresponding enhancement to social connections. The experimental system presented here enables users to share camera phone images with social groups simply by taking a photo during composition of a message. Along these lines, the MobShare system (Rantanen et al. 2004) supports group-wide sharing of camera phone photos with reduced barriers to sharing, although changes to photo sharing behavior and social interactions due to the group context are not reported in their work.
1.3 Mobile Group-Based Communication
The commercial system UPOC (www.upoc.com) that supports group-wide text messaging reports usage numbers that underscore the potential for group-based messaging systems: UPOC reports accounting for 4% of all text messaging traffic in the United States (www.upocnetworks.com/about-us.html). UPOC, however, only provides support for basic group-based