Integrating CiviMail tracked links with Google Analytics
It's possible to add tokens to a url - I was concerned that the token wouldn't get replaced before CiviCRM sets up the redirect url for tracking links. I've tested this and the token is replaced first, so it's possible to use tokens in a correctly formatted GA campaign url (using https://support.google.com/analytics/answer/1033867?hl=en ) that's still tracked by CiviCRM.

I haven't done this with a 'real' mailout, just test runs - I've various things to sort out on the Google Analytics end, and will update this answer if anything relevant arises.

Obviously there are privacy issues about sending contact info to Google - I'm probably just going to use the CiviCRM ID, but if anyone has any recommendations about which tokens would add value to GA data, do let me know.