Although it's hard to see on this picture taken in Marseille last week, it represents the maximum distance between two persons using the same iPhone headset.

Collaborative usage of music if you want and headset proxemics.

Why do I blog this? Collecting behavior like this leads me to wonder about a new book project about categorizing such habits/practices... Besides, I am fascinated by the use of audio/sound interactions (as "non-optical augmented reality", collaborative practices, etc.).