But I've been able to do this for quite a while now? iCloud already has the feature. Its called aliases.
That would be a manual system and dependent on how hard you try doing it. This patent would make it automatic and invisible. You reply to some website, and this thing generates a completely new address just for that website. You never actually notice it. Just if you tell Mail that you received spam, it tracks it down to that website and remembers that mails sent through that site generate spam.
I suggest that Apple should give a free license for this patent to everybody.