Add protected-audience feature

[ddbeck]

No description provided.

[captainbrosset]

Protected Audience is part of Google's Privacy Sandbox project. Edge has a different proposal for this particular API, called the Ad Selection API.
See https://blogs.windows.com/msedgedev/2024/03/05/new-privacy-preserving-ads-api/ and https://blogs.windows.com/msedgedev/2024/10/08/ad-selection-api-limited-preview/

So the fact that BCD shows both Chrome and Edge as supporting Protected Audience feels wrong.
Edge generally mirrors Chrome by default, but this is one case where it probably shouldn't.

I'll try to find more information to (possibly) fix BCD.

[captainbrosset]

Protected Audience is part of Google's Privacy Sandbox project. Edge has a different proposal for this particular API, called the Ad Selection API. See https://blogs.windows.com/msedgedev/2024/03/05/new-privacy-preserving-ads-api/ and https://blogs.windows.com/msedgedev/2024/10/08/ad-selection-api-limited-preview/

So the fact that BCD shows both Chrome and Edge as supporting Protected Audience feels wrong. Edge generally mirrors Chrome by default, but this is one case where it probably shouldn't.

This is more complicated than I thought. Chrome and Edge basically support the same individual BCD keys (with some exceptions), but the overall feature that these BCD keys contribute to isn't the same in Edge and in Chrome.
While Chrome calls it Protected Audience, Edge calls it Ad Selection API.

And there are some caveats, such as runAdAuction which Edge does support for completing server auctions, but not for local auctions.

[ddbeck]

the overall feature that these BCD keys contribute to isn't the same in Edge and in Chrome

Hmm, that's a bit awkward.

I found this doc about the API shape to be helpful toward this but not sufficiently detailed. I think what I really need here are IDLs for the two APIs, so we can figure out what constitutes evidence of support for the two features. Even if the API surface is very similar, my hunch is that the difference is in configuration dictionaries that the BCD Collector won't detect (or rather won't do anything with by default).

This is likely to be a feature that really demands #1173.

[captainbrosset]

I found this doc about the API shape to be helpful toward this but not sufficiently detailed.

Yes, that's the right doc.

I think what I really need here are IDLs for the two APIs, so we can figure out what constitutes evidence of support for the two features. Even if the API surface is very similar, my hunch is that the difference is in configuration dictionaries that the BCD Collector won't detect (or rather won't do anything with by default).

I've started an ms-internal discussion to try and help here. While the IDLs may be very similar (apart from the ProtectedAudience interface, which won't exist in Edge), I think they will work differently. For example, runAdAuction won't do exactly the same thing in Chrome and in Edge.

This is likely to be a feature that really demands #1173.

Definitely!

[ddbeck]

@captainbrosset Were you able to learn anything more about the difference between the protected audience and ad selection APIs? I ask because it looks like protected audience is going away, so being able to mint a (discouraged) feature would be desirable. But that would require know whether Edge is keeping some or all of the API or dropping it too, given the previous discussion here.

[rviscomi]

Tagging in @samdutton to comment on the status of the API

[samdutton]

Protected Audience is deprecated in Chrome.

FYI @kevinkiklee (Dev Rel for Protected Audience)

goo.gle/ps-status has feature status for Privacy Sandbox APIs.

[captainbrosset]

Were you able to learn anything more about the difference between the protected audience and ad selection APIs? I ask because it looks like protected audience is going away, so being able to mint a (discouraged) feature would be desirable. But that would require know whether Edge is keeping some or all of the API or dropping it too, given the previous discussion here.

Edge will be removing the equivalent downstream API along with the deprecation effort too.

[captainbrosset]

Discussed on the meeting: It would be nice to have a tombstone feature for it. Removal date+reason. Don't know if there is docs for this on MDN. But on some features, there's info like "pending removal".
Two ways: we could mint 2 features, with overlapping keys (Edge and Chrome). Or mind just 1 (Chrome-one, and pretending the Edge one doesn't exist). Would be nice to do this in the next couple of weeks before Chrome 150, which is removing the features.

@ddbeck will update this PR.

[ddbeck]

Just needs a description. I don't think we need to put a ton of work into this, if it's not being developer further. Maybe this is sufficient?

Suggested change

	description: The ad selection API
	description: The ad selection API facilitates showing advertisements to users based on interest groups that prevent re-identification of users within the group.

[captainbrosset]

We could also just pretty much reuse the Protection Audience API description since both APIs are for the same use case:

Suggested change

	description: The ad selection API
	description: The Ad Selection API facilitates advertisement sales by allowing sites to register users as part of an interest group or to choose which ads appear based on those interest groups, while minimizing the ability of advertisers to track specific members of the interest group.

[ddbeck]

@captainbrosset I've sorted this out, I think. Would you have a look? The only missing thing is a description for the ad selection API.

Edit: I also sent mdn/browser-compat-data#29723 upstream, to reconcile Chrome and Edge's different statuses with the actual API.