Spam can mean many things. Much of spam is the typical phishing, infected attachment, or scam type emails.

Technically in the U.S., if you opt in to receive offers, newsletters, etc. from an organization at some point, this isn't considered spam.

Even if you accidentally opt in, you should have an easy way to unsubscribe. This makes reporting of these types of emails pretty low.

You have to keep your spam report numbers very low as the sender of such things, if you want to be allowed to continue to legitimately send them.

I like this analogy. It would be interesting to see a similar mechanism to banner ads. I'd imagine part of the responsibility would be on the ad network and part of it would be on the publisher.

Showing a bunch of low-quality "1 weird trick ads?" the network gets flagged. Trying to squeeze too many ads onto a single page? Publisher gets flagged.

I doubt we'll see such a thing. On the other hand ad networks like the deck, carbon and yoggrt have done a good job filtering out bad ads. I generally whitelist sites with those networks.

I too doubt that we will see explicit mechanism for users to manager/report ads on a website, but I do predict that we will keep seeing ads on website even if adblocking reach 100%. For example, online stores normally has a "if you like this product, then you might also like this other thing", a advertisement that I doubt will be blocked any time soon. Similarly, streaming services like to recommend films and music, and that feature is something I hear some people really want to have and would be upset if it went away. Youtube dedicate a lot of page space for this, including the front page, the top of the side panel, the top of the search result, and the end of every video.

The upside of those kind of ads is that they are intended to be both a useful tool for the user and a revenue source, and they must be designed carefully to remain both.