App-to-Web and X-Device

[bmayd]

In the August 8, 2022 meeting we discussed changes to the ARA for app-to-web which shifts responsibility for attribution from the browser to the OS. I think it is worth considering how this change might impact potential cross-device attribution supported by browser data synchronization given the requirement that normal attribution logic in the browser is halted when OS-supported attribution is enabled.

With web-to-web, browser instances could share state through periodic back-end synchronization. Assuming state changes between browser instances which impact attribution are appropriately accounted for (e.g. report submission coordination, user preference changes, data deletion, etc.), it could provide a wider view of the activity of a logged-in account in the web-context and not reveal more information than would be revealed if the user used only a single browser instance.

With OS-supported attribution, the primary context shifts from the web to the device and the data store includes data from multiple contexts: the web context shared by all browser instances (there’s one web) and each of the app, application, etc. context on the device.

In the two models above, data sharing happens within bounded contexts (the web and the device) and no information is shared across contexts. However, synchronizing OS-supported attribution data across devices would require combining information across multiple independent device contexts, thus leaking information unique to each device to the other devices.

Assuming there is a desire to support both cross-device and cross-app attribution scenarios, a potential mitigation strategy would be to allow campaigns to configure attribution to be either cross-device/intra-app (browser supported) or cross-app/inter-device (OS supported). In the former case, attribution logic would not need to be halted, in the latter it would.