EFF Calls for Ban on Behavioural Advertising

Just wait until eye/face-tracking becomes a pervasive thing in VR/AR.

It's not just "hey, we saw that you were looking at this a lot, so you must be interested".

It's also, "User #8187489923323 has recently and consistently expressed slight disappointment when looking at their reflection in the mornings - the next time this happens, play an ad for the latest antidepressant tailored to their demographic with their favorite song in the background"

Online retail companies will never stop collecting and leveraging first party data - their own users making purchases on their own sites.