As long as you could still target based on: - location of ip address - article/page the ad is placed on You could get targetting down to a very small number

As long as you could still target based on: - location of ip address - article/page the ad is placed on You could get targetting down to a very small number of people, and consequently make advertising very cheap. Because of the degree to which paid advertising us about creating common knowledge that a product exists, ads of this sort are likely more useful to the advertiser anyways, at least in the long run. If you merely want to inform people that your product exists, there are usually cheaper forms of marketting.