And yet, with all this information about me, they still struggle to come up with even the slightest big of relevant advertising. 99.9% of the products I see advertised to me are either completely irrelevant to me or products I down right hate: and I never buy them. If they do have all the information the article claims, it just doesn't seem like they're able to use it in an effective manner. So what's the harm?

the key here, is, just don't buy products you don't want or don't need. as long as you do that, you'll be fine. I have yet to meet a single Ad that forced me to buy a product I didn't really want or need. And, just don't let the ads manipulate you.