I can't help but wonder why they didn't try harder to fix spam.
As far as i've been able to tell, it'll be same-old/same-old: Mark as spam, possibly automatic filters.
It seems to me that part of the answer to the question "What would e-mail look like if invented today" should be "there would be no spam".
Couldn't it be done by request/approve like on Skype/Facebook or something more advanced like reputation or something?