These differences tell us much about ourselves. Asynchronous technologies tend to be efficient in that messages are generally short and to the point. More important, both E-mail and voice mail increase our sense of control in that we can send, receive and respond to messages entirely at our convenience. Finally, since a physical record remains, asynchronous messages are inherently more formal, less personal and more guarded. You never know who might see an E-mail or listen to a voice mail.
Synchronous communications are, of course, generally the opposite.
It still amazes me how many Europeans include their mobile number on their business cards and accept calls constantly throughout the day, even at the dinner table. A similar trend is under way in Japan, where wireless PBXs are becoming popular. These systems essentially replace the standard company desktop telephone with a pocket phone that employees carry with them for use anywhere throughout the office complex. I used to think that most of these differences were due primarily to economic pressures. In the downsizing during the 1980s, many of us lost our secretaries and were too busy to even think about answering someone else's phone.