Possibly stupid question, but why not stop e-mail spam in the same way we do IMs?

I don’t see how I could ever get spam-messages from, e.g. an xmpp account. Worst-case scenario is that I get a bunch of ‘subscription’ requests, and I can only add friends when I trawl through the requests, or if I know they’re adding a request at the time, then look out for that request.

Emails seem to let everything in, with a reliance on the admin to sort this out. Why not do the same thing?

Specifically, I’m thinking of writing a script:

1. If this person’s in my contact-list, they’re cool.
2. If they’re on the shit-list, they’re deleted.
3. If not, they get into the ‘waiting room’.

… then set up a shortcut to put someone on the shit-list. So there’s no more ‘you’ve got mail’ notifications from random spammers, and I can review it once a week or so to pull the good-guys out.

Seems like a good idea, but then I wondered, why hasn’t this been done before? If the script works, it seems like someone could do the same thing with a GUI.