MIT has setup a network that watches anyone carrying an activated Wi-Fi device on their campus. Whether it is a laptop, cell phone, PDA you show up on a computer map accessible to any MIT network user. Your identity can be revealed if you allow.
MIT developed electronic maps that track users day and night. This works due to recent wireless network upgrades that now extends to the entire 9.4 million square foot campus. Since the upgrade study labs are used less; cafes and lounges used more.
One map with red dots shows concentrations of users, while another with yellow dots shows individual users with their names if available. "This raises some serious privacy issues," said Director Ratti, whose lab created the maps. Source