By now most internet users know their online activity is constantly tracked. No one should be shocked to see ads for items they previously searched for, or to be asked if their data can be shared with an unknown number of “partners.”But what is the scale of this surveillance? Judging from data collected by Facebook and newly described in a unique study by Consumer Reports (PDF), it’s massive, and examining the data may leave you with more questions than answers.
What they apparently don't have is an international SIM.
