"He spent 1/3 of his time at work answering emails!" Outrageous!
vs.
"He spent 1/3 of his time at work communicating with the other workers." Yeah sounds about right, if not a little low.
The other thing nagging at me is that this feels like Cal Newport woke up one day, got annoyed at his inbox and wrote a whole book about it. I'm all for re-thinking and re-designing, but I'm becoming increasingly skeptical of people who hate email or whatever, and want to re-make the world in that image. It's like the people who get all pissy when it's raining out. Tony Soprano would say, ay it's fuckin' raining, but whaddyagonnadoo.
Interruptions, yes, those are harmful. But that's why there's email. I guarantee an email is easier to delay than someone calling, instant-messaging or physically approaching you. It's got "mail" right there in the name; far as I'm concerned that means you have free license to delay for a day or multiple days, just like the postal service. Check it once or twice a day, during times when you're not trying to concentrate, and then close out of it. Anything useful, copy it to where it belongs (task list, calendar, etc.). If it needs action at some point, mark it "Pending." After that, archive that shit and forget it. If you get too much, tell people to stop sending it. Or just take so long replying that they stop. I dunno.