Except, you know, if you signed up for it, you should really try to do the right thing and unsubscribe. Can't remember whether you signed up for it or not? Maybe you're signing up for too many things (and, yes, I agree that there's far too much of "sign up to find out more!").
Many people don't understand the why's of something, so when they hear 'don't ever press an Unsubscribe button' they never hit unsubscribe buttons, even for services they know they signed up for. People will remember things when it is most inconvenient for you.
Also, they may have signed up to find out more because they wanted to find out more right then. After they learned more, they no longer cared. Since they no longer cared and there was no presented way right then to indicate they don't care, they may look at further marketing emails as spam, especially when there is a lot of them and not a simple follow up 'we miss you' a couple of weeks later.
Just because you know you're not sending out spam, doesn't mean that what you are sending doesn't look like spam to the receiver.
It actually saddens me that pressing the "Spam" button in Gmail has a material impact on the company that sent me the email. I use that button to mean "Get this out of my hair. Unsubscribe, bin it, set a filter to ignore them - whatever, I just don't want to see it any more!"
That Google then turns around and treats my signal as an indication of the level of trustworthiness of the whole company, and then uses this level for other users is actually irritating to me. I'm just using the user interface in the most convenient manner to me. Yes, I should go and unsubscribe - but that's laborious, and clicking "Spam" isn't.
There needs to be a 'best practices' for the unsubscribe option. In the ideal case, you click unsubscribe in the email and are taken to a webpage either confirming your choice or asking you to click a single confirmation button. But sometimes you have to re-enter your email address to unsubscribe, or login to your account to do so.
If I'm reading email on my phone I don't want to have to spend 30 seconds entering my email address or looking up the password for some account I haven't used in months. In the worst case I've lost my password or someone else has used my email address by mistake, and then I'm forced to find the password reset option, re-check my email, and change the password just to unsubscribe. By that point just clicking 'spam' and getting the email out of my inbox starts to sound like a good idea.
It takes at least five seconds out of my life. Sure, not much. But certainly more than the 0.5s it takes to hit the keystroke to mark as spam.
And that five seconds is a lowball estimate if the unsubscribe link is actually to a "manage your email notifications settings" page as is so common these days.
I can kind of sympathize; many email providers have made it really easy to flag something as spam. Compare one click which submits it as spam and moves you to the next email, to multiple clicks, perhaps with some scanning of text on the unsubscribe page, which probably took some time to load, not to mention that the unsubscribe link might be anywhere in the message.
IMHO, unsubscribe links should take one click, and should be at the top of the message, clearly marked. Even if you accidentally click it, so what? Just have another link on the resulting unsubscribe page to immediately undo the unsubscribe. Also, having better support in mail clients for unsubscribe mechanisms (I know Mailman puts in a header with an unsubscribe link, clearly labelled), would be a good idea. I could even see spam handling systems getting a little more sophisticated (if they aren't already), and attempt to unsubscribe via methods in the email first, then if that same email address gets any more email from that source, autoblock it as spam.
