Paul, Thanks for taking the time to respond and explain. This is a useful for me to refer to when explaining this to the reader. Warm regards,
Garrett On Thursday, 16 July 2026 at 13:48:55 UTC-4 Paul Jensen wrote: > Garrett, > > > When we marked the Protected Audience API as deprecated, in > crrev.com/1545185, this included more of the API surface into the > “Fledge” Blink use counter. You can see we added “DeprecateAs=Fledge” to a > lot of the APIs in navigator_auction.idl in that change. It wasn’t > actually an increase in API usage, it was just a change in measurement. > You can see there were no corresponding spikes in particular API usage: > https://chromestatus.com/metrics/feature/timeline/popularity/3855 > https://chromestatus.com/metrics/feature/timeline/popularity/3857 > > On Tuesday, July 14, 2026 at 10:50:58 AM UTC-4 Garrett Johnson wrote: > >> I'm a researcher in this space who has ongoing research >> <https://ssrn.com/abstract=4983927> measuring the adoption and use of >> Privacy Sandbox tools. >> >> I'm hoping that someone in this chain could resolve a mystery for me >> about the Fledge usage metrics in the Chrome Platform Status data here >> <https://chromestatus.com/metrics/feature/timeline/popularity/4188>. >> Basically, this approaches 0% of page loads in Q4 2025 as you would expect >> given its retirement. However, usage spikes to its highest ever usage in Q1 >> 2026 (peaking at 7.7%). This is unexpected: as mentioned above, auctions & >> interest group activity has gone to almost 0 in the Chrome Platform Status >> data (and my own). My guess is that some deprecation flag is being counted >> here, but I really don't know. Other researchers >> <https://arxiv.org/abs/2606.26390> found a similar spike in the HTTP >> Archive data. >> >> I'd really appreciate your input here in setting the record straight on >> whether PA API's post-retirement was in fact a mirage. Big bonus points if >> you can explain why this happened. >> >> Sincerely, >> >> Garrett Johnson >> Associate Professor >> Questrom School of Business >> Boston University >> https://garjoh.com >> >> On Wednesday, 1 July 2026 at 14:25:39 UTC-4 Daniel Bratell wrote: >> >>> LGTM3 for steps 2 and 3. >>> >>> /Daniel >>> On 2026-06-25 19:05, Chris Harrelson wrote: >>> >> LGTM2 >>> >>> On Thu, Jun 25, 2026 at 9:56 AM Yoav Weiss (@Shopify) < >>> [email protected]> wrote: >>> >>> LGTM1 >>>> >>>> On Fri, Jun 12, 2026 at 2:32 AM Paul Jensen <[email protected]> >>>> wrote: >>>> >>> Hi API Owners, Protected Audience API was deprecated in Chrome-144 with >>>>> a plan to remove it in Chrome-150. Currently the usage is 1.1% of >>>>> page loads. >>>>> <https://chromestatus.com/metrics/feature/timeline/popularity/4188>We >>>>> are proposing the following as next steps for removal and associated >>>>> timelines: 1. M150: Remove all Ads API-related entries from Chrome >>>>> settings and UI surfaces (e.g., chrome://settings/adPrivacy) via >>>>> field trial. After this point, all API invocations for field-trial >>>>> enabled >>>>> browsers will always reject. Since the API can already be disabled for >>>>> one >>>>> of many reasons, scripts must already handle such rejections (or they’re >>>>> already significantly broken). 2. M152: Permanently remove the >>>>> underlying implementation code for the API, and replace it with a >>>>> lightweight stub API. The stub will remain removable via field trial. >>>>> >>>>> 3. M152 Canary/Beta: Begin a controlled rollout of the stub API >>>>> removal via a field trial. 4. M152 Stable: Assuming there are no >>>>> regressions or breakage after reaching 1% stable, we will request >>>>> additional approval for full removal at this stage. >>>>> >>>>> At this time, we are seeking LGTMs for steps #2 and #3. >>>>> >>>>> Thanks, >>>>> >>>>> Paul >>>>> >>>>> On Wed, Nov 12, 2025 at 11:30 AM Vladimir Levin <[email protected]> >>>>> wrote: >>>>> >>>> LGTM2 >>>>>> >>>>>> On Wednesday, November 12, 2025 at 11:30:32 AM UTC-5 Chris Harrelson >>>>>> wrote: >>>>>> >>>>> LGTM1 >>>>>>> >>>>>>> On Fri, Nov 7, 2025 at 11:04 AM Paul Jensen <[email protected]> >>>>>>> wrote: >>>>>>> >>>>>> Intent to Deprecate and Remove: Protected Audience >>>>>>>> Contact emails >>>>>>>> >>>>>>> [email protected] >>>>>>>> >>>>>>> >>>>>>>> Explainer >>>>>>>> >>>>>>>> https://github.com/WICG/turtledove/blob/main/FLEDGE.md >>>>>>>> >>>>>>>> Specification >>>>>>>> >>>>>>>> https://wicg.github.io/turtledove/ >>>>>>>> >>>>>>>> Summary The Protected Audience API provides a method of >>>>>>>> interest-group advertising without third-party cookies or user >>>>>>>> tracking >>>>>>>> across sites. >>>>>>>> >>>>>>>> Following Chrome's announcement >>>>>>>> <https://privacysandbox.com/news/privacy-sandbox-next-steps/> that >>>>>>>> the current approach to third-party cookies will be maintained, we are >>>>>>>> now >>>>>>>> planning to deprecate and remove >>>>>>>> <https://privacysandbox.com/news/update-on-plans-for-privacy-sandbox-technologies/> >>>>>>>> >>>>>>>> the Protected Audience API (along with certain other Privacy Sandbox >>>>>>>> APIs, >>>>>>>> as outlined on the Privacy Sandbox feature status page >>>>>>>> <https://privacysandbox.google.com/overview/status>). >>>>>>>> >>>>>>>> Blink component >>>>>>>> >>>>>>>> Blink>InterestGroups >>>>>>>> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EInterestGroups%22> >>>>>>>> >>>>>>>> Web Feature ID >>>>>>>> >>>>>>>> None >>>>>>>> >>>>>>>> Motivation >>>>>>>> >>>>>>>> Chrome has announced that the current approach to third-party >>>>>>>> cookies will be maintained. Since that announcement there has been >>>>>>>> virtually no interest in the Protected Audience API. Use of the >>>>>>>> joinAdInterestGroup() API >>>>>>>> <https://chromestatus.com/metrics/feature/timeline/popularity/3855> >>>>>>>> has decreased by almost 100x and use of the runAdAuction() API >>>>>>>> <https://chromestatus.com/metrics/feature/timeline/popularity/3857> >>>>>>>> has decreased by more than 10x. Of the auctions occurring today, >>>>>>>> virtually >>>>>>>> none of them have winners (determined by looking at the “Success” >>>>>>>> bucket >>>>>>>> count of the Ads.InterestGroup.Auction.Result UMA), implying that they >>>>>>>> are >>>>>>>> not providing useful benefit to the pages initiating them. >>>>>>>> >>>>>>>> Initial public proposal >>>>>>>> >>>>>>>> >>>>>>>> https://privacysandbox.com/news/update-on-plans-for-privacy-sandbox-technologies/ >>>>>>>> . >>>>>>>> >>>>>>>> Developer-facing impact >>>>>>>> >>>>>>>> Given that virtually none of the Protected Audience auctions >>>>>>>> occurring today have winners, we estimate the lost utility from this >>>>>>>> removal to be negligible. >>>>>>>> >>>>>>>> User-facing risks >>>>>>>> >>>>>>>> The user-facing risks are small. While removing the JavaScript API >>>>>>>> could cause pages to break, the impact should be limited to sites that >>>>>>>> don't employ standard defensive coding or feature detection, which >>>>>>>> should >>>>>>>> be rare since not all browsers implement the API. >>>>>>>> >>>>>>>> If usage warrants, we will take steps to avoid any risk of page >>>>>>>> breakage, e.g. by temporarily retaining a stub implementation of >>>>>>>> Navigator >>>>>>>> APIs joinAdInterestGroup(), runAdAuction(), leaveAdInterestGroup(), >>>>>>>> clearOriginJoinedAdInterestGroups(), getInterestGroupAdAuctionData(), >>>>>>>> canLoadAdAuctionFencedFrame(), createAuctionNonce(), >>>>>>>> updateAdInterestGroups(), protectedAudience.queryFeatureSupport(), >>>>>>>> deprecatedReplaceInURN(), deprecatedURNtoURL(), and >>>>>>>> adAuctionComponents() >>>>>>>> that mimic current behavior when a user has disabled Protected >>>>>>>> Audience. >>>>>>>> >>>>>>>> Estimated milestones >>>>>>>> >>>>>>>> Planning to deprecate in M144 and remove in M150. >>>>>>>> >>>>>>>> Currently 0.22% >>>>>>>> <https://chromestatus.com/metrics/feature/timeline/popularity/4188> >>>>>>>> of page loads use the Protected Audience API. These are driven by a >>>>>>>> small >>>>>>>> number of third-party ad tech scripts present on a large number of >>>>>>>> sites. >>>>>>>> We will continue to monitor usage as well as provide comprehensive >>>>>>>> updates >>>>>>>> on privacysandbox.google.com with the status of the API and >>>>>>>> deprecation plans >>>>>>>> <https://privacysandbox.google.com/overview/status>. >>>>>>>> >>>>>>>> We will also proactively work toward reducing usage to low levels >>>>>>>> once this intent is approved, including disallowing any new enrollment >>>>>>>> sign-ups, and contacting enrolled sites to inform them about the >>>>>>>> deprecation timelines. >>>>>>>> >>>>>>>> Protected Audience features that were never launched beyond 20% >>>>>>>> Stable (TextEncoder support >>>>>>>> <https://github.com/WICG/turtledove/issues/961#issuecomment-2793763963>, >>>>>>>> >>>>>>>> Creative scanning via BYOS/V1 trusted scoring signals >>>>>>>> <https://groups.google.com/a/chromium.org/g/blink-dev/c/EXfp34Qb1oc/m/oaiY6MENBwAJ>, >>>>>>>> >>>>>>>> Selectable Reporting IDs >>>>>>>> <https://groups.google.com/a/chromium.org/g/blink-dev/c/1cWqBPHngd0/m/gSYeR_dPAAAJ>) >>>>>>>> >>>>>>>> will be ramped down by the end of 2025. >>>>>>>> >>>>>>>> Protected Audience services, Bidding and Auction services >>>>>>>> <https://groups.google.com/a/chromium.org/g/blink-dev/c/CyXJz3xOEcc/m/1snkv2KhAwAJ> >>>>>>>> >>>>>>>> and Trusted Key Value service >>>>>>>> <https://groups.google.com/a/chromium.org/g/blink-dev/c/fH8u7ZTNZg8/m/oo0WVw7SAQAJ>, >>>>>>>> >>>>>>>> will not onboard new clients once deprecation is approved. We will >>>>>>>> work >>>>>>>> with onboarded clients and plan to turn down the services by the end >>>>>>>> of >>>>>>>> year as usage is negligible today. This will have no user-facing or >>>>>>>> web-compat impact. >>>>>>>> >>>>>>>> Link to entry on the Chrome Platform Status >>>>>>>> >>>>>>>> https://chromestatus.com/feature/6552486106234880 >>>>>>>> >>>>>>> -- >>>>>>>> You received this message because you are subscribed to the Google >>>>>>>> Groups "blink-dev" group. >>>>>>>> >>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>> send an email to [email protected]. >>>>>>> >>>>>>> >>>>>>>> To view this discussion visit >>>>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABQTWrnevtY14OMos%2BuDgzXtFwQJ5vzY3hEMmyRFQBKDHBz-9A%40mail.gmail.com >>>>>>>> >>>>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABQTWrnevtY14OMos%2BuDgzXtFwQJ5vzY3hEMmyRFQBKDHBz-9A%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>>>>> . >>>>>>>> >>>>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "blink-dev" group. >>>>> >>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to [email protected]. >>>> >>>> >>>>> To view this discussion visit >>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABQTWrmRRxZO%3D%2BCmt-hfkBBjeR8j4umTer8krMvmAyiVP_1HXw%40mail.gmail.com >>>>> >>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABQTWrmRRxZO%3D%2BCmt-hfkBBjeR8j4umTer8krMvmAyiVP_1HXw%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "blink-dev" group. >>>> >>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>> >>> >>>> To view this discussion visit >>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOmohS%2BRQAUtSUZw%3D4TsVgNOxcuR5aeQhym2CZO-_WmzUnndLQ%40mail.gmail.com >>>> >>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOmohS%2BRQAUtSUZw%3D4TsVgNOxcuR5aeQhym2CZO-_WmzUnndLQ%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "blink-dev" group. >>> >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> >>> To view this discussion visit >>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOMQ%2Bw94fqnFNWSUWQSm7crPrzuLbO6Cz5p9Rg0BLEJsU%3DHPPg%40mail.gmail.com >>> >>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOMQ%2Bw94fqnFNWSUWQSm7crPrzuLbO6Cz5p9Rg0BLEJsU%3DHPPg%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> >>> -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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