Thanks for your feedback mtmail

Just to brainstorm:

Would they buy advertising results via vendors, e.g. https://developers.google.com/third-party-ads/googleads-vend...?

Or/And approach popular browser extensions; popular plugins with an offer to buy data, via GA or other tools?

Regarding ISP's, currently with SSL, i don't see how they do it unless the ISP's are using a man-in-the-middle HTTPS proxy against websites with non-pinned SSL certificates - but that is ilegal, correct? So, i'm still puzzled