Mobile phones represent not only a means of communication, but an increasingly omnipresent computing platform, enabling diverse modes of communication including ambient displays that are tied to bodies and social groups, rather than physical environments. As an example of such a display, we present Damage, a prototype device for mobile ambient awareness of a social group, and discuss design considerations for such devices. Keywords Social computing, ambient display, wearable, tangible interfaces, mobile phones, group communication ACM Classification Keywords H5.m. Information interfaces and presentation (e.g., HCI): Miscellaneous.