It is a bugbear of mine, I guess because I’m both an IT guy and run an internet business. I know you know your stuff, but many seem utterly befuddled by what identifying personal data actually is or how cookies and the internet itself actually works.
The actual stuff that really identifies a person e.g. full name, home address, telephone number, bank details, employment etc etc tends to exist in very few places and obviously everyone knows, or should know, where they have entered such data, and should be very careful where they enter it. None of this, and I really mean none, is accessible by things like Google or Amazon advertising cookies. Even if it was legal to do so, which it isn’t, there is no mechanism for such data to get between the secure website you entered it (e.g. a bank) and a simple anonymised ad tracking cookie.
I certainly advise people to be very, very careful where they deposit real information online, but suggesting visiting the Independent, Allmusic, pfm or whatever has access to any real personal information is just BS IMHO. They just don’t at all. To be blunt I can’t even identify people and I own the site! If I’m trying to ID a troll or sock-puppet chances are I have nothing more than a burner email (gmail, hotmail etc) and can track to a broad geographic region and ISP assuming they aren’t using TOR or VPN (where I just assume guilt and delete the account!). To be honest the technical side is useless, I detect trolls, sock-puppets and other time-wasters as they are always so thick they revert to past recognisable form, e.g. folk banned for racism just start being racist again!
PS A device isn’t a person. As I say targeted ads work via browser history, they are designed to field content of interest. They don’t know *who* you are, only that that browser has been used to look at CD players, bicycles, bathroom taps and catfood or whatever in the past 24 hours, so it makes sense to field more of that sort of stuff rather than car tyres and woman’s shoes. It really isn’t as scary as some folk (especially idiot politicians) make out.