Active Badges and Mark Weiser
I particularly like the idea of the voting system described in this paper, which enabled users to avoid uncomfortable social situations while still providing feedback to better improve their environment.
"We have built a voting application called Arbitron for the PARCTAB system. It has proved particularly interesting in the context of presentations. Audience members with PARCTABs vote on the quality and pace of the material being covered by a presenter. The votes are collected anonymously and displayed on the Liveboard. The board is visible to both the audience and the presenter; the feedback is intended to help match the presentation with the interest and intelligence of the audience."
An Overview of the ParcTab Ubiquitous Computing Experiment
Roy Want, Bill N. Schilit, Norman I. Adams, Rich Gold,
Karin Petersen, David Goldberg, John R. Ellis and Mark Weiser
There is also an interesting paper on the sociology of active badges and looks at why people want to share information with a group.
Why Do People Wear Active Badges?