Did you go to class today? How about the library? Some colleges are finding this information about their students by adding a mobile app and short-range phone sensors to track students around campus. Using networks of Bluetooth transmitters and wireless access points, the app can track attendance and even calculate "risk scores" for academic success based on how frequently students visit the library. Critics say this kind of intrusion into students’ lives represents a new low in invading student privacy on a massive scale, but this style of surveillance has become just another fact of life for many Americans. Many apps and programs involve cameras, sensors or microphones that measure people’s activity and whereabouts with striking precision. This tracking of everyday living allows trends to be analyzed for any number of purposes.