Excerpted from This Is Marketing: You Can’t Be Seen Until You Learn to See by Seth Godin, in agreement with Portfolio, an imprint of Penguin Publishing Group, a division of Penguin Random House LLC. Copyright © Seth Godin, 2018.

More than 20 years ago, in Permission Marketing, I narrated the beginning of a revolution.

It’s about attention. Scarce attention.

Marketers had been stealing it, abusing it and wasting it. Spam was free, so spam some more. Spam, spam, spam.

Email spam, sure, but all sorts of spam. Constant efforts to steal our attention and precious time, which we can’t get back.

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There’s an alternative. The privilege of delivering anticipated, personal and relevant messages to people who want to get them.

That hardly seems controversial, but it was. It got me thrown out of the Direct Marketing Association.

What I saw 25 years ago was that spam didn’t scale. That attention was truly precious, and selfish marketers needed to stop stealing something that humans couldn’t make any more of.

My team and I built a company around this idea. At one point, Yoyodyne was sending, receiving and processing more email than anyone else on the planet … and we were doing it with the active permission of every person we engaged with. Our open rates were over 70 percent and our emails averaged a 33 percent response rate.

That’s about a thousand times the rate of a typical commercial email sent in 2018.

Before paying for ads, then, long before that, begin with the idea of earning this asset. The privilege of talking to people who would miss you if you were gone.

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Permission marketing recognizes the new power of the best consumers to ignore marketing. It realizes that treating people with respect is the best way to earn their attention.

Pay attention is a key phrase here, because permission marketers understand that when someone chooses to pay attention they actually are paying you with something valuable. And there’s no way they can get their attention back if they change their mind. Attention becomes an important asset, something to be valued, not wasted.

Real permission is different from presumed or legalistic permission. Just because you somehow get my email address doesn’t mean you have permission to use it. Just because I don’t complain doesn’t mean you have permission. Just because it’s in the fine print of your privacy policy doesn’t mean it’s permission either.

Real permission works like this: If you stop showing up, people are concerned. They ask where you went.

Permission is like dating. You don’t start by asking for the sale at first impression. You earn the right, over time, bit by bit.

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One of the key drivers of permission marketing, in addition to the scarcity of attention, is the extraordinarily low cost of connecting with people who want to hear from you. Drip by drip, message by message. Each contact is virtually free.

RSS and email and other techniques mean you don’t have to worry about stamps or network ad buys every time you have something to say. Home delivery is the milkman’s revenge: It’s the essence of permission.

Facebook and other social platforms seem like a shortcut, because they make it apparently easy to reach new people. But, the trade-off is that you’re a sharecropper. It’s not your land. You don’t have permission to contact people; they do. You don’t own an asset; they do.

Every publisher, every media company, every author of ideas needs to own a permission asset, the privilege of contacting people without a middleman.

Permission doesn’t have to be formal, but it must be obvious. My friend has permission to call me if he needs to borrow five dollars, but the person you meet at a trade show has no such ability to pitch you his entire resume, even though he paid to get in.

Subscriptions are an overt act of permission. That’s why home delivery newspaper readers are so valuable, and why magazine subscribers are worth more than newsstand readers.

Related: 5 Ways to Get to the Heart of Emotional Marketing

In order to get permission, you make a promise. You say, “I will do x, y and z; I hope you will give me permission by listening.” And then — this is the hard part — that’s all you do. You don’t assume you can do more. You don’t sell the list or rent the list or demand more attention. You can promise a newsletter and talk to me for years, you can promise a daily RSS feed and talk to me every three minutes, you can promise a sales pitch every day (the way internet retailer Woot does). But, the promise is the promise until both sides agree to change it. You don’t assume that just because you’re running for president or coming to the end of the quarter or launching a new product that you have the right to break the deal. You don’t.

Permission doesn’t have to be a one‑way broadcast medium. The internet means you can treat different people differently, and it demands that you figure out how to let your permission base choose what they hear and in what format.

If it sounds like you need humility and patience to do permission marketing, that’s because it does. That’s why so few companies do it properly. The best shortcut, in this case, is no shortcut at all.

How many people would reach out and wonder (or complain) if you didn’t send out that next email blast? That’s a metric worth measuring and increasing.

Related: How Billion-Dollar Companies Think Differently About Customer Relationships

Once you earn permission, you can educate. You have enrollment. You can take your time and tell a story. Day by day, drip by drip, you can engage with people. Don’t just talk at them; communicate the information that they want.

Shortly after Permission Marketing was published, Dany Levy started an email newsletter called DailyCandy. It was a city‑focused email alert for young women looking for local sales, parties and connections. The asset was so valuable that she ended up selling it for more than a hundred million dollars.

And every podcaster has an asset like this, a subscriber base that regularly listens to the latest show.

And every successful politician has an asset like this, a group of activist voters eager to hear the next riff and share it or take action.

Protect it. It’s more valuable than the laptops or chairs in your office. If someone walked out the door with those, you’d fire them. Act the same way if someone on your team spams the list just to make a metric go up.