You can also use Smidge without sending us any PII, but obviously segmentation will be limited.

Also in the next couple of weeks, with just a user id, you will be able to place a call directly from Zendesk (for example) without us knowing anything about the user.

Can you make it so I determine the user segment on my end and just send you the user id and segment id? I'd totally use this then.

Yep absolutely. You bucket users on your end and just pass through the user Id and the segment name. Then mirror the segment as call groups on our end e.g. segment='high value'