In this paper, we introduce a prototype system designed to support mobile group socializing that has been appropriated for everyday use by 150 users over 18 months. The system supports cross-channel communication, allowing users to participate in group conversations using text messaging, instant messaging, email and the web. It does this with the "console," a uniform text-based syntax that enables the prototype to be used over a variety of mediums. We found that participants used the system mostly for adhoc coordination rather than chat, with pervasive, crosschannel group communication supporting an informal "half-invite" style of invitation. We examine why coordination dominates over chat, suggesting that crosschannel mobile group messaging serves a distinct role, different to traditional text messaging, instant messaging and email. Furthermore, we found differences in the content and usage habits across channels, for example messages sent from a computer were mor...