> Users' could opt in to what they are targeted for to ensure it is the relevance they want

So much this. I would turn my adblock off, if I had a directory with checkboxes/weights against interesting product topics. I would even browse the topics themselves regularly, as I did in google directory before it was gone. I (and the economy) want me to discover, not to hide from pushiest pushers around.

Modern marketing is just a slowpoke idiot who stalks me for two weeks after I already bought a <productname> via search.