It's not actually what they do, it's what they don't do. I just unsubscribed from a newsletter. I would have preferred to just change my email address, but they didn't give me that option. So, I unsubscribed. I clicked the unsubscribe link in the email and immediately received a confirmation that I was unsubscribed. There was no request to confirm my unsubscribe, no option to resubscribe just in case I had unsubscribed in error, and worst of all there was no opportunity for me to explain why I chose to unsubscribe. Every unsubscribe page should give your soon-to-be-former subscriber an oppportunity to tell you why they unsubscribed. Geez! In today's world, we need all of the customer intelligence we can get. Often, all you have to do is ask and they'll tell you what they think. Your customers' opinions are really the only ones that matter.
Here's what I think is going on: I think those of us who use email to communicate with our customers and prospects are so scared of being called spammers that we sometimes go to ridiculous extremes to avoid that label. Look, there's a big gulf between permission-based email marketing and spamming. If you're following CAN-SPAM, you're not spamming. Sure, you'll occasionally get a complaint from someone on a high-horse who doesn't remember subscribing to your list, but the reality is that permission-based email communication is much more socially responsible than flooding postal mailboxes with paper, it's more financially responsible to your shareholders, and when done ethically and properly, it's much more customer-friendly than postal mail. The key here is "permission-based" email communications. As long as that's what you're doing, make it easy for your customers not only to unsubscribe, but also to communicate with you as to their preferences, their email addresses, and their reasons for unsubscribing.
