One Inbox or Inbox Zero?

Since when does "Inbox Zero" refer to email?

When I first heard of the idea of an empty inbox it did not refer to you email inbox - instead it referred to a very physical inbox and to the management of workflows. Merlin Mann did an excellent Job of tying the inbox metaphor in the context of inbox zero to the email mailbox with his article series.

In GTD (getting things done) the inbox is something quite different

From what I understood from the GTD book by David Allen the point of an GTD-Inbox is twofold. First to get things out of your mind quickly and secondly to have one place of reference for your tasks/todos. Once you have that you can apply the two-minute-rule and other things from the GTD toolkit.
So actually in this model the inbox is a logical container for all the stuff you have to do.

Using the email inbox as a todo list harms your work organization

If my inbox is tied to the email system my work is tied to my computer. Assuming I wanted to set up a workflow system that is more pull oriented and does not necessarily contain only virtual to dos I would have to somehow bend your email workflow and it would be hard to use a different tool for your workflow management. Although I have to admit that there was a time when I had email folders called "Pending", "In Progress", "Waiting" and "Done" - but they didn't have WIP-Limits and it was at a time before David Anderson had even begun to write the Software Kanban Book.

Goals of the Inbox

Having one place to collect all todos is far more important for me than having an empty "unsorted pile" - which basically is what the "inbox" really is.

"Email Inbox Zero" is quite random IMO

Why the heck are so many people possessed with getting their (email) inbox to zero? What about their Twitter Inboxes, their Skype Inboxes their paper inboxes, their... you get the picture. So instead of trying to achieve inbox Zero I just scan my emails whenever they arrive or I have the time to do it. If I think I have to act upon one of them I create a ToDo in a secondary system. If I need to reply, i create an empty response, save that (so that don't have to search for the original) and create a ToDo in a secondary system.
The todos in this secondary system are completely independent from my mail workflow, my inbox contains literally tens of thousands of emails and I don't have any problem with that.
And I don't spend hours of thinking about ways to find an effective way to abuse my email system.

Plain text is king? Pen and Paper?

So what magical secondary system do I use?
None at all.
Right now I work with a three tiered approach consisting of Pen and Paper for the first tier, and two documents in plain text that get synchronized between all my devices.
I guess everybody has to find their own solutions. But that is not the point. The point is: It is not you E-Mail inbox and copying, deleting or moving hundreds of emails per day might even eat up time that you could spend getting things done.

Cheers
Michael

(This post is v0.9 but the ship date has arrived...)