One of my spam peculiarities is that I really dislike spam being delivered to me even if it's been tagged as spam and gets immediately filed away into the far depths of the filesystem, never to be seen again. Back when I was more actively involved in anti-spam stuff, I spent a fairly large amount of effort not just recognizing spam but rejecting it at SMTP time; not just because it was the right approach when possible, but because I actively liked having that happen. Unfortunately, these days (for various reasons) far less spam going to me gets rejected at SMTP time than gets filed away. All of which is a round-about explanation for why I care about a self-serving wish and dream for people doing 'email marketing'.

Namely:

You know all of those web bugs and tracking beacons that email marketers spread all over their email messages? I wish that they'd actually use them. I don't care so much if they use them to send more spam to people who actually read and respond to their messages; what I wish is that they'd notice when people don't, when there's no indication that their email is going to anywhere except a black hole. When they notice this lack of activity, they could perfectly well cut back their email sending activity to that address and eventually stop.

(They could get around how email clients these days don't show images by default by making the images an intrinsic part of the message, so that people who are actually interested will enable the feature and let themselves be tracked.)

Of course, all of this is an impractical dream and I know it; there are endless numbers of reasons that even nominally reputable email marketers can find to not stop sending spam to addresses, no matter how absurd the excuse.