A list I had subscribed to has been sending an email to me every day. Too much for my tastes, particularly as most of them are just pitches. There are a few 'good' emails, but by-and-large just too many, too frequently.
I clicked the 'Unsubscribe' link, and at the top of the page was a message saying something to the effect of: "Wait! Before you unsubscribe, will you give me another chance? If you click the link below, I'll only email you a 'digest' once per week...."
Rather than unsubscribe as I was about to do, I went ahead and clicked the link which - I assume - moved my into a list that will only receive a once-weekly email.
Anyway, I thought it was a pretty clever way to 'hold onto' a subscriber. It probably isn't going to work in every circumstance, and if the 'digest' isn't reasonably valuable, I'll unsubscribe from that as well, but this marketer did manage to keep me from unsubscribing altogether for the time being.