Use case for Audience Extension about turtledove

[michaelkleber]

Good question! I briefly mentioned something close to this in the Browsers Joining Interest Groups section:

This could be on WeReallyLikeShoes.com, or could be a cross-domain iframe — maybe RunningShoeReviews.com writes articles about shoes sold by WeReallyLikeShoes.com, and the review site has an agreement which lets the retailer add people to an interest group with 'name' : 'reads-reviews'. It should also be possible for a site owner to include a cross-domain iframe without giving it this capability.

As you point out, this could also be used by a publisher to build an interest group of their own readers, with some arrangement later for what advertisers or ad networks get to run ads targeted at that group. Is there any important difference here that we need to account for?

By the way, I believe the use case you're describing is mentioned under the name "Audience Selling" in the Advertising Use Cases doc being developed by the W3C's Web Advertising Business Group.