Google+ userId into google analytics for attribution modeling

Question

Due to the nature of my website, it is very complex to get a proper attribution model, cross device tracking is complex but necessary.

I would like to know if it is possible to obtain somehow a users google+ userId whenever he visits my site.

I know there is a feature called UserId where I need to generate my own ID and track it upon a customers visit, but due to the nature of my website, there is very little probability they will log in prior to converting (Fact which will make every cross device interaction useless).

Answer 1

You cannot use a Google ID as the User ID in Google Analytics. The User ID must be private and non PII, ie Google must have no way to determine who that ID belongs to. Obviously if it's a Google-based ID, they would be able to tell pretty easily.

The relevant bit from the TOS is paragraph 7 :

You will not (and will not allow any third party to) use the Service to track, collect or upload any data that personally identifies an individual (such as a name, email address or billing information), or other data which can be reasonably linked to such information by Google.