We have our "built-in" conversion tracking of clicks vs PoPs.

But some customers may want to set up other goals, and track against them. For example:

Custom Goal: where the value of a guests existing room stay has increased within 15 days of a click of an email

or

Custom Goal: where a guests PoP segment has changed from Lapsed back to an active segment, within 30 days of receiving an offer.

etc.