the density of space

I’ve been thinking a lot lately about one of the challenges Matt Webb raised in his Movement presentation:

Webb, Matt. Movement. Schulze & Webb, 02008.

“The challenge I’m thinking of is this: how do we make group software for groups that already exist? I can’t even think how to design a good sign-in system that doesn’t require usernames and passwords.”

— Movement, Matt Webb (38)

One idea I had was to base authentication/authorization on residual proximity. Proximity to other members of a group during a meeting would leave traces in an attender's device (e.g., phone, PDA, camera, or even an RFID-enabled object) that would act as a key to shared resources. Over time, the traces would decay, eroding access. Eventually, in order to renew their access, a member would need physical proximity with other group members. Other variables could influence the level of access (including length of exposure to other group members, which members of the group one was exposed to and how long one goes without encountering other members).