WiFi "Marauder's Map" at MIT

In Cambridge MA, maps displaying names and locations of users
on MIT's wireless network were unveiled this week - projected
onto large Plexiglas rectangles that hang from the ceiling.
They are also available online to network users, the data
time-stamped and saved for up to 12 hours.

Red splotches on one map show the highest concentration
of wireless users on campus. On another map, yellow dots
with names written above them identify individual users,
who pop up in different places depending where they're logged in.