[kinsomo]

> Your ad-network should practically "steal" your content-targeting information to divert on-topic ad money to entirely unrelated sites

Do you have a link to support that? I believe it, but I'm looking for an article that explains it well. I read one that had a good example of an advertiser basically telling the operator of a high-quality, premium site that he's only going to use them to gather audience targeting information so they can be targeted at cheaper sites.

[usrusr]

The tiny "share on facebook" button, a google analytics script and so on, you don't even need to show an ad to associate my browser identity with the topics on the site I am visiting. But ads can certainly serve the same purpose.

Maybe you misunderstood what I meant (my wording wasn't exactly perfect), I'm not talking about some dramatic ad-fraud scheme: without tracking-based targeting, all ad-money about scuba-beekeeping (just making up some really small niche) would go to the few sites dedicated to pleasures scuba-beekeeping. This is how Google started their dominance, they were the best at automatically matching scuba-beekeeping advertisers to scuba-beekeeping websites. Content-based targeting.

With tracking, ad-networks show a small, cheap ad (or even just some tracker the site includes without monetary compensation) on the scuba-beekeeping site and take a note that the browser identity a target for scuba-beekeeping. Ads about scuba-beekeeping will now appear to that browser-identity on random news sites and the like while the niche site won't see a cent for the targeting information.

All in all, if the "native" ad market (the one addressable by content-based targeting) of a site has above-average value per eyeball, a site will tend to lose more from cross-site targeting than they will gain from showing ads unrelated to their content (but related to whatever their visitors have visited before), if the "native" ad market is lower then they may win. Visit frequency also plays a role, if the content-targetable sites take only a small percentage of their users' browsing activity, a no-tracking scenario would cause a bidding war amongst on-topic advertizers, if they take a large chunk of their users' browsing, inbound tracking targeted ads (about other topics) could easily more than make up for the losses in on-topic ads.