They do more than that.
"MIT researchers did this by developing electronic maps that track across campus, day and night, the devices people use to connect to the network, whether they're laptops, wireless PDAs or even Wi-Fi equipped cell phones.
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."
Pretty interesting stuff.
Former Webhost... now, just a guy.