Hi everybody, I was wondering how it is possible to specify a custom ClientID My users first have to register and next on my thankyou page the user has a unique Id assigned to him. like this: http://mysite.com/thankyou/index.php?guid=6C9CF45A-D316-41EA-92B0-B6FD078077CC At this point I want to store this GUID from the url as the ClientId of the user. How do I do this? I tried with this code: First I grabbed the id from the url <?php $guid = $_GET['guid'];?> and then I added this into the GA script: ga('create','UA-42733428-1',{'clientId':'<?php echo $guid; ?>'}); However this seems not to be working, as I don't see the id appear in the GA cookie. Thank you!