Increase joinAdInterestGroup Duration Capping in FLEDGE

[xxia2021]

Introduction

In the current FLEDGE proposal, the duration specified in the joinAdInterestGroup() call is capped at 30 days.

Ask

Increase the duration cap from 30 days to 90 days.

Reasons For This Change:

• Valuing a range of advertiser needs: a short duration capping is ignoring the needs for a wide range of advertisers as not all products are a short term decision buy (e.g. car, travel, jewelry purchases).

• Other guardrails for IG volume management: Additionally, constraints such as cap on number of IGs/adtech and k-anonymity will automatically ensure that each ad-tech streamlines the number of IGs it stores and maintains over time.

• User Experience impact: Increasing the duration cap should not harm user experience significantly, nor violate the goal of privacy sandbox. While users might be triggered from a RMKT ad that lingers around, ad-tech is incentivized to retain only those IGs over 30 days where the product purchase decision is likely to be relevant for longer, and use other techniques, such as frequency capping, to improve the user experience.

[michaelkleber]

Hi @xxia2021, could you please update your GitHub profile with your name and company affiliation?

The 30-day data retention timeframe is in line with other Privacy Sandbox advertising APIs, like the 30-day limit in Attribution Reporting and the 3-week lookback in Topics. This seems to be the sweet spot that balances ad tech desires with user and privacy advocate expectations of effect lifetime.

Recall that the browser isn't imposing any limit on first-party data lifetime. So when a person comes back to your site, you are welcome to add them to an IG reflecting things they did on that same site more than 30 days ago.

[sashagavrilov]

+1 to increasing the duration. 30 days is to low for high consideration B2C and for B2C for both measurement and re-engagement.