As is the norm for email deliveries, we always include an unsubscription link in the footer of each delivery. This unsubscription links takes the recipient to a Campaign web application where they can manage their preferences, opt-in/out etc.
What I want to be able to do is whenever a recipient opts-out, identify the source from which they came. Specifically I want to identify the delivery that contained the unsubscription link they clicked on.
I've read the documentation related to tracking in web applications here: