Technically, how does "Unsubscribes from Email" work?
Something I had never thought about much has come up as an issue and I was hoping someone could help shed a little more light on this.
I've moved from having Unsubscribe HTML/Text globally defined to using {{system.unsubscribeLink}} inside an email template. This works just fine and, because the behavior is not default (no form passing--one click unsubscribe), I have a smart campaign that manually flips the record to Unsubscribed. What I'm curious about is how Marketo uses the trigger and filter for Unsubscribe(d|s) from Email. Does it determine this via the form fillout itself or just via the click? While I realize I can just as soon set up workaround filters/triggers for visiting web page in conjunction with an email, I'm curious to know what the actual criteria is for the system default trigger and filter.