Eavesdropping on Electronic Guidebooks: Observing Learning Resources in   Shared Listening Environments
  We describe an electronic guidebook, Sotto Voce, that enables visitors to share audio information by eavesdropping on each other's guidebook activity. We have conducted three studies of visitors using electronic guidebooks in a historic house: one study with open air audio played through speakers and two studies with eavesdropped audio. An analysis of visitor interaction in these studies suggests that eavesdropped audio provides more social and interactive learning resources than open air audio played through speakers. 
Allison Woodruff, Paul M. Aoki, Rebecca E. Grinter, Amy Hurst,   Margaret H. Szymanski, and James D. Thornton