Link decoration in contextual/FLOC

[BasileLeparmentier]

Hi Michael,

reopening issue #28 as you closed it.

Do you mean that somehow the browser would clean / filter any 'link decoration'?

UTM_source, one of the most frequent 'link decoration' in use today, is a backbone of advertising measurement, championed most notably by Google Analytics ("GA"), the largest website traffic monitoring tool in the world. It is used by advertisers to compare performance and shift budget between different marketing channels, exposing a full range of signals, from clicks, to bounce rate, to sessions, to conversions, etc.

UTM_source is not so much a way to declare where the user came from, but rather how he arived on the website ('Facebook_video_ad', 'criteo_consideration', 'google_retargeting', etc...). This usage does not seem to infringe any of the Privacy Sandbox principles. Sure, nothing enforce the fact that UTM_source is used in this fashion. But it is an important usage nonetheless, if only for accountability. And rather than killing it, it would be better to make it more robust.

Losing UTM_source would mean that GA becomes obsolete for the Open Web, as many of these signals, crucial for advertisers (especially when they use contextual advertising, are gone. Do you plan on giving enough flexibility in the Conversion Measurement API to cover all current GA metrics?

GA also extends beyond Open Web display and video impressions, to encompass a full suite of Google first party assets like Youtube, Gmail, Search, Shopping, etc. The 'level playing field' that you guys mentioned a few weeks ago during our weekly calls certainly means that GA wouldn't use link decoration or anything of the sort to track performance outside of open web, giving these proprietary channels an unfair advantage in the process, correct?

Extending the argument, will these channels be subject to noise, delay, and high level aggregation as well?