The Global Inbox versus the Distinct Inboxes

When it comes to organizing multiple accounts on an email client, there are two major approaches - one is to send them all to a shared inbox, generally called a global inbox. How emails get filtered or sorted at that point varies, whether by folders or by labels. The other approach is to keep separate inboxes and sent/outbox/junk/trash folders for each mail account set up in the application.

Most desktop email clients offer the option of both inboxes global and separate, but it gets trickier with the constraints of the small viewports on mobile screens.

The way the iPhone OS has been doing it these past couple years seems to be consistent with the way the original iPods menus were done - you start a root level menu, and drill your way down (visually to the right) until you reach the level you wanted to visit. For example, on the original iPods, playing a song from the main screen involved: Music > Artists > Jack Johnson > All Songs > Upside Down, and going back (up one level) was done by the menu button (or the equivalent home button on the iPhone OS devices).

This was part of the foundation of the famed ease-of-use menu/clickwheel navigation of the iPods, and to the extent of the menu/home UI breadcrumbs, the iPhones and iPod touches. However, for tasks where switching quickly between two children-level items, heavily nested levels can hinder that. For example, one classic task is to switch between folders in two separate email accounts. From the first inbox, this requires going back two levels up emailone@someprovider.com > Accounts > emailtoo@someprovider.com > Inbox. That's four steps.



Now try this on the Palm Pre's webOS. For those maintaining separate inboxes, the accounts are listed in collapsed folder lists, so if both accounts's lists weren't expanded already, two taps for expanding both are required, after which both inboxes are just a scroll away from each other, and one tap for going back to the accounts list. If that's not enough, this mail client allows adding folders from various mail accounts into a global favorites list on the accounts list page, reducing even the need for a scroll.



The fact that there's a global inbox view while preserving the separate nature of the accounts ("All inboxes" on webOS) is a huge side perk, and actually excels beyond what many desktop applications offer. This is a shining example of a solid mail client implementation for both global/distinct inbox camps that scales well onto the mobile platform.