> I think this is a myth. The unsubscribe link, from everything I've seen since CAN-SPAM a decade ago, almost always works.
Define "works"? Does clicking "unsubscribe" for advertiser A stop mails from advertiser A? Yes, probably. But what stops advertiser A from sharing his unsubscribe list with advertiser B? Well, nothing -- it's legal and an advantage if advertiser B reciprocates by sharing his list right back.
There's nothing to keep an advertiser from sharing his "unsubscribe" list with any number of other advertisers -- the only legal requirement is that he not mail you again.
A list of people who unsubscribe from mailing lists would be the least valuable list in the world. I can't imagine anyone knowingly paying money for that. What you describe is possible, but I really don't think it's at all common.
You aren't thinking like a spammer. A spammer only cares that the addresses on his list are read by humans. And the possible uses for a list of live human readers isn't limited to spam -- there's also phishing to consider. Someone who recognizes spam and clicks "unsubscribe", after a few days might react differently to an e-mail apparently from Microsoft's security department alerting the user that, since Windows XP is about to drop dead, Microsoft has decided to protect the user with a special security update -- just click the handy link.
Spammers might be deplorable and slimy, but they're not stupid.
> What you describe is possible, but I really don't think it's at all common.
If it can be done, spammers will do it. I can see you're having a hard time thinking like a bottom-feeder, perfectly understandable, so to help your comprehension, I offer the Miracle Man scam:
Define "works"? Does clicking "unsubscribe" for advertiser A stop mails from advertiser A? Yes, probably. But what stops advertiser A from sharing his unsubscribe list with advertiser B? Well, nothing -- it's legal and an advantage if advertiser B reciprocates by sharing his list right back.
There's nothing to keep an advertiser from sharing his "unsubscribe" list with any number of other advertisers -- the only legal requirement is that he not mail you again.