for three decades I worked in this field of endeavor and we call it TA or Traffic Analysis. It is surprising how much information you can derive from analysis of communication links. This was 1947-1977 time period before the digital and very limited. With digital it is a piece of cake. The problem is what safe guards are there to stop those going outside the envelope. With this administration there is no limits. This is clearly evident with IRS, DOJ, State Dept, and the executive branch taking advantage of these resources.