Bruce Schneier discusses the dangerous side of Big Data. From my own experience with an internet startup 10 years ago I fully agree to his conclusions. Data is a toxic asset, and storing data about should be avoid whenever possible. This is a clear contradiction to Big Data, where you store as much as you can get.
Read his blog on toxic data here: https://www.schneier.com/blog/archives/2016/03/data_is_a_toxic.html
Or better, read his complete blog – its worth the effort.
„Data is a toxic asset“