For those of you who just received the email about getting David's tips for managing email, I would like to offer the following three suggestions. I have been teaching this modified version for six years, and it has been working very well. As David says, "as simple as possible, but no simpler".
1) Instead of having a single "Action" folder, create the following subfolders within the "Action" folder. Keep nothing in the "Action" folder, but rather keep all your actionable emails in the subfolders.
Add Saturday and Sunday if you choose. Keep your daily folder open, not your inbox, and at the end of each day it should be empty. All actionable emails should either have been done or moved to a different day.
2) Check your Waiting For folder first thing in the morning. A quick review stops the nagging in your mind, and for any that you followup on, the person will have time to get back to you that day.
3) If you are cleaning out your inbox for the first time, create a folder called "Backlog", pick a date where the bulk of the emails are now irrelevant (say, two months ago), and move all those older than that into the backlog folder. They are not lost, but now you can spend your time wisely by processing the rest of the last two months to empty. That way, you can actually get to the place where you experience a completely empty inbox, with all your actionable emails in your daily folders, with no distractions of reference, someday/maybe, waiting for, and all the rest. It is a great feeling, and experiencing it once will make you want to keep it that way. However, processing 10,000 emails in your inbox is awful, and probably not worth the time for most of them (old, outdated, no longer relevant). If you feel motivated to do them later, slowly clean out your backlog folder. If you haven't visited it in six months, considering tossing or archiving the whole folder.
Other than that, set up your email as David describes. Setting up your email is the single fastest and easiest way to experience the clear head that GTD promises. It is a self-contained microcosm of the GTD system that introduces you to the terms and process. That's why I teach it. Most people can be up and running in under ten minutes, and have a completely empty inbox over a lunch hour or two.
Try it. You'll love it.