Campaign to mark the //ZEHN anniversary party: before the party took place, guests were invited by post to register themselves via a website (1). The guests’ movements during the party were visualised on screens (2). Following the party, a web-link was sent out via mail (3) which enabled the guests’ movements to be reconstructed. This was made possible with the help of user-tracking based on active transponder technology. The guests at anniversary party became part of a real-time installation: when 'checking in' each guest was given a transponder armband which made it possible to pinpoint their location at any time. Using terminals it was possible for guests to search for, find and monitor people. The current location details of each person were displayed on four large screens.