Inbox zero is nothing to be proud of. It says you've elevated triaging mail into real work.
If you spend all that time keeping your high score for dealing with mail, I'm impressed if you can fit in anything proactive.
Since Outlook email search became good enough, I've even given up on filing mail; I just leave it all in the inbox and rely on being able to find it when I need it.
I use my phone to triage my email; since Windows Phone started showing me the first line of each message, I've been able to delete a lot of things straight away, deal with the important things I spot and leave the rest unread "for later".
And that's how I ended up with inbox 4,000.
Usually, around about February, I declare what I call email Chapter 11 - it's like email bankruptcy but instead of deleting all the unread messages, I archive them by year (so it's a bankruptcy you can come back from).
I have to wait till February, because I need all my December mail for CES and CES keeps me busy for most of January. And for the last couple of years, February and March and April have been busy; plus I no longer keep all my email on my PC and selecting hundreds of emails in an Exchange search is slow enough to hang Outlook. So instead of dropping back down to something more approachable, my unread count just kept going up.
It didn't really bother me; I was mostly on top of what mattered. But I did sometimes feel like I was in Our Mutual Friend, where the kindly Boffin family makes their fortune sifting through the dust heaps of Victorian trash to uncover the occasional treasure.
And then I turned on Clutter in Office 365 and I noticed something. After about three days, once the system had trained itself, not only was I seeing the emails I really cared about, with only a few extraneous "maybe later" messages. But my unread count wasn't creeping up any more. The messages I'd want to delete would be in Clutter, and I could blast through them quickly to check and clear them.
My inbox is now so empty I can easily spot real mail; that means I don't have to worry about losing messages in the flood, so I don't have to check mail as often. Theoretically that leaves me more time to work without distractions, but I have no trouble finding distraction so the notifications on the Microsoft Band I'm trying out are proving useful.
But with my unread count finally peaking, it was worth taking the time to file those "maybe later" messages (they're useful to search through when I'm doing research and besides, there's enough useful email in there that I'm not deleting it all, but I don't have the time to tell them apart without Clutter). The day I got under inbox 1,000 - without having archived 2014 yet - had all the festive feeling of achieving a badge in Untapped or an Xbox achievement (gamification works like any other stimulus and reward system).
But every time I leave Clutter for a few days without checking for something it's filed too aggressively, if I've been ill or extra busy, I get much more of a warm glow - because I can't remember anything really important ever getting sent to Clutter. But there are all the duplicates, the newsletters I didn't sign up for (and a couple that I did but are only useful when I'm away), the off topic pitches, the unsolicited comment, the offers to write my articles for me (I really dislike those) and all of the other email cruft - out of the way and not subtly making me feel I've fallen behind.
I've always said Office 365 is far less work than running your own Exchange Server and cheaper to boot (especially on a domestic energy tariff). Clutter makes it much more useful too (because even a large business isn't going to build, maintain and continually update the many clusters of servers needed to power this kind of machine learning system).
Making Clutter work for you
Clutter is built in to Exchange in Office 365; your admins have to enable it for the tenant and then you have to turn it on in Outlook Web Access.
At that point it starts watching how you deal with email - what you read, what you forward and reply to, what you delete and what you ignore.
After a couple of days, it will start moving the messages it expects you to delete or ignore into the Clutter folder. You can help train it by moving them to the Clutter folder yourself - in any mail client where you read your Exchange mail - or you can just carry on ignoring them and deleting them when you get round to it. (If you use OWA you'll see a Mark as clutter option on the context menu for messages in the inbox and a Move to inbox icon on every message in the Clutter folder, but Clutter gets the same signal about a message however you move it.)
Clutter carries on training all the time. It waits a week to be sure you're ignoring a new message rather than just being busy, before taking it as an example of a message you won't bother reading. New messages that seem similar to its probabilistic machine learning engine will get moved to Clutter as soon as they arrive, so if you start ignoring different kinds of messages, Clutter will learn that. Clutter also uses the Office Graph to work out who your boss is and who reports to you, and mail from either won't be treated as clutter.
If Clutter gets it wrong, move the message back to your inbox in any mail client and - after a training period - similar mail won't get filed again. Untraining Clutter like that can take a couple of days, and the training changes are applied once a day, so you might end up moving two or three messages back to the inbox while the system is figuring out your habits.
If you move a message just before the once a day update, the next one like it will still go into Clutter - but the one after that should stay in your inbox. If you tried Clutter and found it got much too enthusiastic and filed everything, turn it back on and try again; that was a specific bug that you'd run into if you turned it on during one specific period, and it's been dealt with.
For some people, Clutter doesn't have much to work with, because they already have rules that file most of their messages - and Clutter doesn't deal with messages that you're filing with rules.
It works on any email that doesn't get filed that you either read, delete or don't look at for a week - and it has to have enough of those to find useful patterns.
That makes it most useful for the 'piler' rather than the 'filer' - because the filer doesn't have a pile of mail to be sorted.
At the very least, it will find those stray newsletters you've not got around to unsubscribing from and put them in one handy list. At the best, it will tame the flood of email and give you back a usable inbox. And it's up to you how much unread mail that can have in.