At the moment we're in a situation where private companies are collecting more data than the police and security services (at least in the UK).
The UK police would never get a warrant to collect this data like this on ordinary citizens who are not suspected of crimes.
All this data is being quietly collected in the background by apps, bundled up and sold on.
Most users aren't giving their informed consent: either they've given no active consent at all; or they believe they've consented to eg receiving weather reports for their location. They have no idea the extent of the tracking, and the number of different sources of data which are now being combined.
Facebook using people's Likes of music and car-repair shops to target messages that "Dems are pro Black people" vs "Dems are anti Black people" will seem like very small beer when the mass-surveillance chickens come home to roost.
The incredible thing is, this hasn't been driven in the first instance by the bodies one might think to be wary of, eg governments (enemy or friend) and state security apparatus. This has been driven by advertiser wanting to sell you their brand of washing powder; and by Facebook & Friends wanting click revenue from the washing powder salesfolk. This is why they've worked together to build these surveillance structures.
Makes me boggle.