: A mobile device can be used as a prop, to facilitate the interaction between the user and people in the proximity and to actively convey a specific impression to them. Based on field studies and interviews three aspects of mobile devices used as props are described: warm versus cold devices, how they convey a specific impression by association to similar devices and specific situations of use, and how the characteristics of a mobile device influence the body language of the user. Collaboration, digital camera, emotional usability, information appliance, mobile phone, Palm Pilot, PDA (Personal Digital Assistant)