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. 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/878c2b34-9d94-4882-bbfe-f29d8aff0553n%40chromium.org.
