It’ll make ads harder to target, and as such lose a lot of relevance. It means ads will become less useful and more of a nuisance than they are now. If people are gonna jump up and rejoice at the demise of ad agencies, they need to hold their horses and remember a lot of sites are supported by ads. Though I do not like ads, and it doesn’t help me because I’m in a country which doesn’t get served by major ad agencies, I understand the necessity of their existence and the vital role they play in the web ecosystem. Ads are a huge driving force of the “free” web and stifling the ad agencies will not benefit the cause of furthering the web a whole lot.
I can understand how people may find being tracked scary but I have never heard of people coming in harm’s way due to being tracked by ad agencies. It’s probably a big issue in individualistic society like US where people want to be alone and left alone. I understand being afraid of being tracked by govt. agencies, but ad companies? Meh.