Patterns of Group Usage

This is a technical proposal for an algorithm to find patterns in spatio-technical data. They propose the idea that buying behavior could be predicted from group identity, which could be determined by movement and proximity data.
This is not a usage-centered or design oriented paper, but it brings to light some interesting issues for those areas.

On Mining Group Patterns of Mobile Users, 2003
Yida Wang, Ee-Peng Lim, and San-Yih Hwang
[full-text pdf]