My normal process in Yahoo! Mail is to read a new message and store it in a User folder immediately, unless I need to respond. I regularly sort mail into about 10 User folders (out of 25). Ultimately, I'd like to streamilne the Move process.

The "Move" button / menu at the top of the email reader pane lists the User folders alphabetically. On my browser, I see the first 5.5 folders before I need to scroll. My current workaround is to rename the most common User Folders to start with numbers so they get pushed to the top of the User folder list, but that only affects the few visible entries.

When organizing my Inbox or another folder, the left pane starts with a set of default links (e.g., Inbox,Trash) and dividers that cannot be hidden or moved. This leaves room for 4.5 User folders at the bottom before scrolling. The Inbox is locked at the top of the list. As a result, I'm constantly scrolling up and down between the Inbox and User folders.

I want to edit the User Folders list and the left pane to prioritize frequently used items and suppress unused ones. This could be implemented in various ways. Personally, I'd like a screen to edit the list order, priority, grouping folders, names, etc. Alternately, you could add a parent folder / group for the default items so I can collapse them. Or you could separate the left panel into sections for Quick Access and All Items. You might even keep a list of 5 recently used folders in the Quick Access panel. If you wanted to be really fancy, you could try to predict the folder I want based on my prior selections for similar emails, like my iPhone does.