MIT's WiFi "Marauder's Map"

Here we go: Have we learned nothing from The Matrix?

The Marauder's Map in the Harry Potter books shows where all the students and teachers are in real time. MIT's wireless network lets students and faculty opt in to having their locations plotted and displayed.

The maps were unveiled this week at the MIT Museum, where they are 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.