Is Android advertisingId unique per device or per user account?

Question

i tried to find out if the new Advertising Id from Google is unique per device or per google account? In general i would like to know what happens if someone has two devices connected with the same google account?

Same Question for the iOS IDFA.

Thanks in advance Philipp

Answer 1

AAID is a "device-specific, unique, resettable ID for advertising" - https://support.google.com/adxbuyer/answer/3221407?hl=en

Answer 2

As I look into developers page, I understand that Ads ID is user-specific unique (so unique per user not per device)

http://developer.android.com/google/play-services/id.html

The advertising ID is a unique but user-resettable string identifier that lets ad networks and other apps anonymously identify a user. The user's advertising ID is made available to apps through APIs provided in Google Play services.

Regarding iOS, as I checked reference, this is device-specific unique

advertisingIdentifier

An alphanumeric string unique to each device, used only for serving advertisements. (read-only)

https://developer.apple.com/library/ios/documentation/AdSupport/Reference/ASIdentifierManager_Ref/ASIdentifierManager.html