The Problem

You're a fresh grad at widgets.com; after a successful internship last summer where your boss convinced you you did something useful, you are now managing their advertising campaigns, trying to reach new customers and/or achieve some kind of performance metric, using your budget effectively while delighting existing and potential clients. It's a lot.

You are able to target an appropriate user set, not show them the same Limu Emu ad too many times, and understand if they've paid for your widget based on the wonderful tools that Chrome gives you. You send your Grandma a link, so she can be proud of your clever usage of Interest Groups, the Attribution API, and Bard 0.2 (you're on a budget, you can't afford ChatGPT!) generated textual creatives. She buys a widget to show her support, and sends you a card saying how proud of you she is. It's a lot.

Now Grandma goes to use her Android "Cell Phone Device" and opens the widget purchase thank you email to clear the notification. But now, she keeps getting ads from widgets.com even on her "Cell Phone Device". She is sad and confused. She wonders if you got her card. She wonders if you care that she is on a fixed income. She worries aloud, why does he keep showing me ads for widgets I already bought, but the widget ads just won't stop! It's too much!

She tries to find a family counselor she can afford with her Medicare Advantage plan. But the counselor's ad bids low because it isn't aware she's in the TechSavvyGrandma Interest Group on her laptop, and due to Medicare cuts the plan's ads never outbid your highly optimized Interest Group based re-targeting campaign, which never fails because the WASM execution in Chromium is bug free. Angry and frustrated, she drops you from her will, you're disinvited from Thanksgiving, and you're left to wonder how you could have solved this "cross device same person same site" problem without losing your family. It's a lot.

Finally your boss fires you because you lost a customer and had significant overspend trying to target an existing customer. "Why didn't you know it was the same person!!!" she demands to know! It's a lot.

Current Solution

In the current ecosystem, "Cross Device" is a technique which allows for coordinating targeting, capping, and attribution/measurement across multiple devices that are agents for "the same person". The way Cross Device works today is, in my experience, based on graph data that is collected through some "foo", and then at ad time the identity expansion is handled server side so that the capping, targeting, and measurement can happen "Across Devices". This would allow you to, for instance, frequency cap and target across a users laptop and mobile, remove someone from targeting after conversion, etc.

PENGUIN for Privacy Sandbox

In the Privacy Sandbox world, Interest Groups, and more broadly user data, are held by the users agent and used in a way that ensures privacy in an on-device or TEE based auction. We believe that doing it this way disables passive tracking the user wouldn't explicitly agree to while maintaining a decent advertising experience that supports publishers creating content.

Enabling targeting, capping, and attribution to happen across device, without additional privacy-attack-vectors, would be a significant improvement in the new-ecosystem's ability to provide publishers incentive to create content and advertisers the ability to advertise in a consistent and privacy respecting way.

In the case of a User who is using the same (or related) User Agents across Devices, and in particular a User Agent that supports some form of Authentication to the tool itself (a la Chrome and Edge), the driver of privacy can still be satisfied if those user agents coordinate with each other while maintaining the same partitioning scheme.

So what I'm proposing for discussion is that the User Agent allow The User to opt-in to this limited sharing within their account, and the Authenticated User Agents then coordinate such that the TechSavvyGrandma Interest Group from Grandma's laptop is also available on her Android "Cellular Phone Device", no one gets disinvited from Thanksgiving, and everyone keeps their job.

(A bird name here could be: PENGUIN (Potentially Enable Narrow Global Useragent Individualized Networking)).

How to Coordinate

I'm more aiming to propose this overall, see what people think about the privacy aspects, and get thoughts. Certainly some kind of coordination could happen server side, which surely has issues; the clients could potentially sync with each other, and then everything would look the same from the auctions perspective (i.e. it doesn't know it's getting a blob from 2 machines), but that has it's own issues.

So since the perfect is the enemy of the good I'm going to say "I'm not sure", but am hoping to discuss this further.