The Google Analytics terms of service does do not allow to track "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".

Does anybody have first-hand knowledge if this includes user ids which cannot be resolved by Google but can be linked to actual persons via an Analytics Users CRM system (e.g. a CRM linked to Analytics via API access) ?

I used to think so, but if that where the case many ecommerce implementations would be illegal (since they store transactions id which can be linked to client's purchases).

If anybody has insights about the intended meaning of the paragraph (preferably with a reliable source) it would be great if he/she could share :-)

2 Answers 2


Well, from what I've gathered from Google's documentation on client IDs and from dimension widening, as long as you're not passing in PII data, you're abiding by the TOS.

I mean, Google outright gives you the documentation to get and client id:

ga(function(tracker) {
  var clientId = tracker.get('clientId');

So you could easily put this into a custom dimension to use in UA. As long as you're not using any personally identifiable information within Universal Analytics, all is OK.

LunaMetrics has put out a blog post about linking MailChimp email campaigns using the client ID with Universal Analytics. From the various conversations I've had with other industry folks over the year, is that having that unique id will allow us to finally connect GA to CRMs, etc.


Here's a bit more reading on the subject too:

A post by Google Analytics Evangelist Justin Cutroni

A thread from the GA product forums

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