The email habits of Tim Cook, Bill Gates and 11 other highly successful people

When a customer emails Bezos to complain about something Amazon-related, which they can very easily do, Bezos often forwards the message to the appropriate person at the company, adding just one character: "?"

"When Amazon employees get a Bezos question mark email, they react as though they've discovered a ticking bomb," Businessweek reported in 2013. "They've typically got a few hours to solve whatever issue the CEO has flagged and prepare a thorough explanation for how it occurred, a response that will be reviewed by a succession of managers before the answer is presented to Bezos himself."

The golden rule for email management according to Weiner is, if you want less email, send less email.

He writes on LinkedIn that the rule occurred to him at a previous company when, after two email-happy colleagues left the company, his inbox traffic decreased by almost 30%.

"Turns out, it wasn't just their emails that were generating all of that inbox activity — it was my responses to their emails, the responses of the people who were added to those threads, the responses of the people those people subsequently copied, and so on," Weiner writes.

"After recognizing this dynamic, I decided to conduct an experiment where I wouldn't write an email unless absolutely necessary. End result: Materially fewer emails and a far more navigable inbox. I've tried to stick to the same rule ever since."

The beauty-sample subscription service CEO told Lifehacker that insisting people on the team indicate when they need a response in all emails is one of her best time-saving tricks.

"It makes prioritization so much faster," she said.

In a fascinating Quora thread about CEO email habits, Michael Chen, a responder who once met Hsieh, wrote that the Zappos CEO told him he had a team of four or five full-time email handlers.

"Fun fact, I think their official titles are Email Ninja," Chen said.

"My boss told me that whenever you're writing a letter — and now it applies to emails today — never start a paragraph with the word 'I,' because that immediately sends a message that you are more important than the person that you're communicating with," Tisch told the New York Times' Adam Bryant.

He says that having to think about how to start a sentence without "I" helps you become a better writer and teaches you how to really think through an issue.

The CEO who wakes up at 3:45 a.m. each day said during an interview with ABC that he receives somewhere between 700 and 800 emails a day.

"And I read the majority of those ... Every day, every day. I'm a workaholic."

Gates told "Today" in 2013 that he only received between 40 and 50 emails a day.

"So you process some, and get back to others at night. You make sure if you put something off you get back to it later," he explained.

Huffington has three simple rules for email:

1. No emails for half an hour before bed

2. No rushing to emails as soon as she wakes

3. No emails while she is with her children

"The last time my mother got angry with me before she died was when she saw me reading my email and talking to my children at the same time," Huffington wrote in her book, "Thrive." "... being connected in a shallow way to the entire world can prevent us from being deeply connected to those closest to us — including ourselves."

The online marketplace CEO told Fast Company that you need to have a system for everything, no matter what it is.

For example, whenever he meets someone new and adds their contact information to his address book, he includes a note about when they met and what they discussed. That way, whenever he emails someone, he can directly reference their meeting before he moves on to the ask.

Goldin considers her morning a critical part of her day and devotes the wee hours of the morning to checking her email and schedule.

She says she heads straight to her inbox at 5:30 a.m. because "doing this gives me a clear understanding of what the next 12 hours are going to look like and what my priorities are once I get to the office."

When overwhelmed with his inbox, Holmes likes to "declare inbox bankruptcy" and delete everything so he can start fresh.

He recommends only doing this once every few years, and practitioners should add a disclaimer message to their email signature after deleting unread mails. Something like, "Sorry if I didn't get back to your last email. To become a better communicator in 2015, I've recently declared email bankruptcy," he advises.

In his book "How Google Works," the former Google CEO wrote, "Most of the best — and busiest — people we know act quickly on their emails, not just to us or to a select few senders, but to everyone."

Even if the answer is a simple "got it," Schmidt says being responsive establishes a positive communication loop and a culture focused on merit.

Zuckerberg tells Marie Claire she has two important rules when it comes to email:

1. She waits at least 20 minutes after she's woken up before she checks it, and 2. She holds off on sending emails when she knows she's feeling overly emotional.

"You'll likely breathe a sigh of relief that you didn't send it once you've read it again," she says.