My Android has a pretty nice universal mailbox, supporting an astounding amount of “direct message” platforms – exchange, IMAP, Yahoo! Mail, facebook and twitter (at least). I like the Inbox0 principle, which means any e-mail currently in inbox is “not having been dealt with”. If I need extensive work, I might move it to a todo folder – the inbox is not a permanent place.
This is thwarted by some mboxes not supporting an option other than “leave it in” or “delete it”. Facebook, twitter – I’m looking at you!