A research study conducted by Northeastern University secretly tracked the locations of 100,000 people outside the U.S. through their cell phone usage. Researchers used cell phone towers to track users' locations when they made calls or sent and received text messages. In another set of records, researchers used cell phones with tracking devices in them and got records for their locations every two hours over a week's time.

The FCC says that this type of non-consensual tracking is illegal in the U.S. The study co-author Albert-Lazlo Barabasi said that researchers didn't know what phone numbers were involved and randomly chose the 100.000 people to provide an extra layer of anonymity to the study.

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