[not_jd_salinger]

I've worked in Ad Tech for awhile now at many different places. While the data and privacy issues that abound are mind blowing, this process:

> sift through vast piles of data, find previously unknown patterns, and then exploit them.

is much harder to pull of sucessfuly than you think. Having worked in the weeds with many projects of this nature, in practice these models are wildly less useful and powerful than the people buying the output from them believe.

For an individual case, you can exploit this data pretty well to find out shocking amount of personal information about a person. Doing this at scale in a way that doesn't converge into noise is much harder.