Lotus Notes had most of this for over a decade. (Score 1)

Lotus Notes has supported multi-folder filing and multi-view display forever (literally since it first shipped for the view features). Notes' views are are queries against whatever search criteria you define. You can also define rules that will auto-file messages into folders on arrival rather than the dynamic search of views.

For a long time, Notes has had the ability to color-code messages in your inbox based on the sender so you could setup the VIP Gold/Platinum concepts mentioned at the blog. Notes 7 also implements attention indicators which are icons representing whether the message is addressed specifically to you individually (very important) or to a small numbers of recipients or bulk mail.