From Columbia mathematician Peter Woit at Not Even Wrong:
To me, Facebook is perhaps the most worrisome of all the Big Data concerns of the book [Cathy O’Neil’s Weapons of Math Destruction ]. It now exercises an incredible amount of influence over what information people see, with this influence sometimes being sold to the highest bidder. Together with Amazon, Google and Apple, our economy and society have become controlled by monopolies to an unparalleled degree, monopolies that monitor our every move. In the context of government surveillance, Edward Snowden remarked that we are now “tagged animals, the primary difference being that we paid for the tags and they’re in our pockets.” A very small number of huge extremely wealthy corporations have even greater access to those tags than the government does, recording every movement, communication with others, and even every train of thought as we interact with the web. More.
See also: Big data raises bigger questions re artificial intelligence