[ghaff]

Yes. But even if you pay for a month placement on a given site, the ad buyer is still going to want an estimate of how many legitimate viewers see/saw your ad.

It probably works better on things like podcasts but the bottom line is that you can't really trust me to tell you how many viewers my site had without some fraud detection mechanisms in place. (And even then fraud is apparently pretty rampant.)

[Xelbair]

>But even if you pay for a month placement on a given site, the ad buyer is still going to want an estimate of how many legitimate viewers see/saw your ad.

yes, you might WANT that. but you do not NEED that. Remember that ad's isn't only effective when clicking on it, but also by spreading visibility of your offer/product.

you could easily use sites visitor count as a estimate for monthly pricing. And frankly without all tracking there would be no incentives to fake click on ads at all, so you could get your own tracking on your own side.

[ghaff]

If I can't tell with some degree of assurance whether you have 1K viewers per month or 1M viewers per month (never mind uniques), I'm probably not going to pay for ad on your site.

[Saris]

I may be missing something, but why? Wouldn't the buyer just look at how many people arrived at their website from the ad?

[jefftk]

Bots can click through like any other visitors. They won't buy stuff, though, so if you're placing ads for people to directly take an expensive action ("performance advertising") you're mostly ok. Brand advertising, though, is very dependent on fraud detection because it doesn't have this clear connection.

There's more about this near the end of the post.

[tobr]

Do you think it’s possible to measure how many people are coming from an ad on a specific site and buying something, without also resorting to illegal tracking?

[jefftk]

That's a good point. I think a shopping site might be able to succeed in arguing that they had a legitimate interest in tracking how people arrived on their site, but possibly not. On the other hand, if half of your visitors consent to tracking that's enough to have a pretty good sense of the value you're getting from each source.

[ghaff]

How do you know those clicks are people? (You can measure just conversions but that's a much higher bar for measuring an ad and a direct conversion may not even be your objective.)