I think that with regard to gmail, the spam problem has shifted back to overly aggressive filtering, rather than being solved. And with Priority Inbox, it seems like it shouldn't have to be that way.

When Priority Inbox was added, the idea of putting all of the adverts I signed up for in one view, and the rest right in front of me was a huge improvement.

The problem is that more and more, I'm finding the things that I actually signed up for end up in my spam folder rather than in this "middle tier" where I can assign them high priority if I care enough about them. Notifications of a new statement from a few banks of mine, not always, but often, end up flagged as spam. Many companies that I do business with and have specifically signed up for their adverts end up flagged as spam. I can whitelist them, sure, but I was so used to accepting that the spammers have won that I hadn't started looking in the spam folder until very recently (and when viewing my inbox, it takes one click to even see that I have new mail being sent to Spam).

Alice.com, Onlive, Godiva, Subway, local mall, local car dealership, credit card "points" account, beautician (if you haven't guessed, I share this account with my bride), all flagged as spam. Of the 71 items, 2 are traditional spam (one for prescriptions I don't need yet, and one with random letters and numbers from a woman I don't know).

Edit: bad grammar on my prt.