Each terminal of a computer network can monitor the activities of the other terminals or associated equipment such as a telephone and display these activities in visual and/or audible form. The display may be represented as a "virtual world", and/or a generative music system such as "Koan". The nature of the activities performed by the terminal itself also control the display, for example giving greatest prominence to those terminals engaged in similar or related activities. A terminal may be configured to act as a specified user's "base" terminal, to display the activity of the specified user, by identifying whether the specified user's identity is being used on another terminal. The activity of this terminal can then be displayed on the "base" terminal. The base terminal can therefore indicate the absent user's availability, level of activity, etc. to colleagues working nearby.