Wouldn't it be nice if mail programs followed any rel='unsubscribe' link found in a message, whenever the message was marked as spam?
It would be nice if everyone that actually allows unsubscription would set the correct headers. In my experience, only traditional mailing-lists do, and all the stuff you really want to unsubscribe to reinvent a new interface over http(s). Which isn't great if you're in an email reader, not a web browser.
If people could get their act together and actually supply an accurate text/plain part to all the "fancy" html crap, that'd be great too.
It always makes me sad when companies realize that they've not got an interesting enough offer that stating it in a short concise text is going to get any conversions, an then assume that if they format it so it's unreadable on a small screen, add a lot of images that'll be blocked for privacy reasons, their offer will be more enticing.
Makes me even more sad that it (apparently) works.
Think about it this way: if there was an auto-unsubscribe mechanism, which ethical bulk email senders honored and spammers didn't, then it would become much easier to filter spam: any message that clusters into a message-cluster that the system has sent out an unsubscribe-request for already, is junk.
Every spammer who wanted to "trick" the auto-unsub mechanism would basically have to first dox themselves for all the world to see. And any certificate that turned out to not be a valid means of contacting the spammer would be quickly revoked.
Because then they can dictionary attack a large list of random emails, send out a trivial campaign, and collect a list of valid users then sell it to someone else.