Why you want to know about Quantcast

Waste is always a problem, who needs to reach people who are not part of the target? Just last week I was on Facebook and saw ads that were so far off that I would have fired the agency responsible if I was the client. So what does Quantcast have to do with this? When you buy tv you only pay for the demo that you target but online you pay for every single impression whether they are targeted or run of site (network). Quantcast changes that, you can buy custom demos on sites and eliminate much of the waste or so the theory goes. So then the question becomes what do I need site ratings for if I can just pull the numbers that fit? Could be an interesting fall season if they decide to push their wares north of the border.