Intent to Prototype: Federated Learning of Cohorts

[Yao Xiao]

Contact emails

yao...@chromium.org

jka...@chromium.org

kle...@google.com

Explainer

https://github.com/jkarlin/floc/blob/master/README.md

Summary

The FLoC API intends to provide callers (primarily ad-tech) with coarse-grained information about the user’s browsing interests, subject to the user’s settings, to aid in interest-based online advertising. The browser’s job in this API is to keep track of user interest (e.g., by monitoring navigation history), cluster that interest into an anonymous FLoC cohort, and reveal that anonymous FLoC value via script and headers.

Motivation

In today's web, people’s interests are typically inferred based on observing what sites or pages they visit, which relies on tracking techniques like third-party cookies or less-transparent mechanisms like device fingerprinting. User privacy could be better protected if interest-based advertising could be accomplished without needing to collect a particular individual’s exact browsing history.

Risks

Interoperability and Compatibility

No signals from other browsers. We hope to get signals from other browsers when we have more evidence that supports the hypothesis that this can be privacy preserving and have advertising utility.

There is no compat risk, as this introduces new headers/APIs only.

Ergonomics

N/A

Activation

The API is straightforward to use but understanding how to interpret the meaning of a FLoC may be complex.

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux,

Chrome OS, Android, and Android WebView)?

Yes

Is this feature fully tested by web-platform-tests?

Not yet but they will be.

Link to entry on the Chrome Platform Status

N/A

[Michael Kleber]

A key part of the reason we plan to prototype this approach is to measure its privacy properties, and study what Chrome can do to minimize any privacy impact.

Unfortunately, the best data we have is that limiting the web to contextual advertising solutions dramatically decreases the ability of web sites to fund themselves — for example, 52% less revenue for sites on average, and 62% less for news sites, according to one source, with similar numbers widely replicated by others.  That's why Chrome is committed to exploring new techniques that support the ads-funded ecosystem but are built with privacy guarantees from the outset.

--Michael

On Tue, May 5, 2020 at 4:41 PM Eli Grey <m...@eligrey.com> wrote:

I am of the camp that firmly believes that anything which intentionally decreases privacy by any measurable amount is an anti-feature.

FLoC feels like a privacy anti-feature to me and I am strongly against this ever shipping without further justification. We should instead be encouraging contextual advertising solutions. Ad networks should target their ads based on the content being viewed, not on the 'cohort' viewing the content.

--

Forewarned is worth an octopus in the bush.

[Eli Grey]

I am of the camp that firmly believes that anything which intentionally decreases privacy by any measurable amount is an anti-feature.

FLoC feels like a privacy anti-feature to me and I am strongly against this ever shipping without further justification. We should instead be encouraging contextual advertising solutions. Ad networks should target their ads based on the content being viewed, not on the 'cohort' viewing the content.

On Tuesday, May 5, 2020 at 8:23:22 AM UTC-7, Yao Xiao wrote: