Outcome-based Dovekey

[jonasz]

The Dovekey explainer makes no mention of the outcome-based extension to Turtledove. In our view, from the perspective of bidding accuracy, the most valuable part of OBTD is the addition of userSignals (a piece of data stored privately in the browser and accessible only by the on-device bidding logic). I was wondering, what are your thoughts on adding it to Dovekey?

[ardianp-google]

Thank you for your interest in Dovekey.

It should in principle be possible to use the information from the fine grained userSignals to construct the lookup key(s) in Dovekey. We imagine that key construction could take place in an ad network-provided function run locally in the browser, isolated from the network, storage and the current webpage context. Such a function can accept a similar set of in-browser signals that were described in the Outcome-based TURTLEDOVE.

For example, a key-constructing function may look as follows:

const constructKey = function(userSignals, recentImpressionAges, …) {
  return userSignals.lastProductViewed + "_" + userSignals.lastVisitDate;
}

Alternatively, as you suggested in https://github.com/google/ads-privacy/issues/14, browsers could provide the usual TURTLEDOVE-style bidding function with the direct access to retrieving values from the KV store. Similarly to the above, and as described in Outcome-based TURTLEDOVE, such bidding functions could access userSignals.