The question would be whether it’s possible to make one’s behavioural data (online or offline) “radioactive” to then prove with a high degree of accuracy whether someone (like Facebook) is stalking you online to deliver targeted ads.
At the moment advertising providers use a lot of data for ad targeting, some of which is benign and/or acquired with informed consent. As a result it makes it impossible for the user to tell whether an ad was targeted to them based on data they consented to share or if the data used was data they didn’t want to be collected or used for advertising purposes.
Could be easy enough if your opponent is not expecting it and deploying countermeasures. Something like a customized AdNauseam https://adnauseam.io/ that prefers clicking some particular crap you don't like.
At the moment advertising providers use a lot of data for ad targeting, some of which is benign and/or acquired with informed consent. As a result it makes it impossible for the user to tell whether an ad was targeted to them based on data they consented to share or if the data used was data they didn’t want to be collected or used for advertising purposes.