There's a feature in Outlook I really like: The ability to pin a folder to the top of the nav pane.
It works like this:
1) Right click any Folder or View in any Outlook mailbox.
2) Click "Add to Favorite Folders".
The Folder or View will now appear near the top of the nab pane, right below the inbox!
I have to use Outlook for my day-job and I make use of this by pinning the most active folders so they're always handy.
I wish Notes provided for this.
I can think of a really easy way to do this: Create a new kind of outline entry type called "Pinned". This would show Folders and Views that have the "Pinned" property.
It might also be good to "Filtered-Pinned" outline types. Then allow users to tag a pinned View or Folder with one or more strings that could be used to do the filtering.
And the ability to show just Folders or just Views or both would be useful.
By the way, when you create local archives in Outlook they show up on the nav on the left and act just like normal mailboxes, including this pinning behavior.