Attention is the only resource that matters

Almost every argument about email marketing eventually reduces to an argument about attention. Should you send weekly or twice a week? Attention. Should your subject lines be short or long? Attention. Should you segment or send to everyone? Attention. Should you write in a personal voice or a brand voice? Attention. All of these are surface questions, and all of them are really the same question underneath.

Attention is the only resource in email that behaves like a scarce commodity. Time is elastic — a subscriber can find fifteen more minutes for something they care about. Money is elastic — a subscriber will pay more for something they want. Attention is not. Every subscriber has roughly the same twenty-four hours as every other, and the share of those hours available for email is small, and shrinking, and decided message by message.

Once you take this seriously, most of the tactical questions in email marketing become easier to answer. The frame is always the same. Does this decision spend the subscriber's attention well, or does it waste it?

The attention budget

A useful thought experiment: imagine that every subscriber on your list has assigned your emails a small monthly attention budget. A generous subscriber gives you twenty minutes a month. An enthusiastic one gives you forty. A casual one gives you five. The budget is invisible, but it is real, and every email you send draws from it.

This frame changes what "sending too often" means. Sending twice a week is not inherently too much. Sending twice a week where each email uses two minutes of the subscriber's attention is fine, for a lot of subscribers. Sending twice a week where each email uses ten minutes of half-attentive scrolling before the reader gives up is a disaster, and the reader's budget has been spent on something they did not enjoy.

The programs that get this right think about their sends as small withdrawals against a limited fund. The programs that get it wrong think about their sends as broadcasts, where more is always better and length is always available.

What this means for length

The right length for an email is the length at which every additional word is worth more than the fraction of a second it costs to read. This is not a fixed number. A weekly newsletter from a writer whose voice the subscriber loves can run to two thousand words and still be worth every one. A promotional campaign from a brand the subscriber tolerates should probably be under two hundred words, because the subscriber's tolerance for that brand is a small budget and every word beyond the essential is a withdrawal.

The test is not whether an email is short or long. The test is whether every word in it is worth the reader's attention. Applied honestly, this test cuts most marketing emails in half.

What it means for frequency

Frequency is another budget question. A subscriber who opens once a week is telling you what their budget looks like. Sending them four times a week is trying to spend a budget they do not have. The overspend does not cause them to give you more attention. It causes them to give you less, more selectively, until eventually they unsubscribe or start ignoring you by default.

Programs that ignore this cadence signal accumulate a specific kind of subscriber — the one who is technically on the list but has trained themselves to skip everything you send. This population is invisible in the top-line metrics and expensive in the deliverability ones.

What it means for design

Every design decision in an email either respects or wastes attention. A three-column layout wastes attention by requiring the eye to decide where to go first. A hero image that takes two seconds to render on a bad connection wastes attention by making the subscriber wait. A subject line that promises something and a body that delivers something else wastes attention twice — once on the false promise and once on the unfulfilled expectation.

The best-designed emails I read are almost embarrassingly simple. One column. One idea. One call to action, or none. The design says: I understand you have limited attention, and I intend to spend as little of it as I can while still saying what I mean to say.

Once you accept that attention is scarce, every other decision in the program follows. Length. Frequency. Design. Voice. All of them are downstream of the same underlying respect for the reader's time.

The compounding effect

Respecting attention compounds. A subscriber who reads two of your emails in a row and finds each of them worth their time gives you a slightly larger budget for the third. Over six months of consistent respect, a program earns disproportionate share of its subscribers' inbox time.

The reverse also compounds. A subscriber who reads two of your emails in a row and finds them both a waste gives you a smaller budget for the third. Over six months, the same program loses share, until eventually the subscriber is opening once a quarter, out of loyalty, and reading nothing.

The direction of the compound is decided send by send, and by the accumulation of small decisions that respect the subscriber's time — or fail to. Every serious email program I care about is, at heart, a machine for making those small decisions correctly, most of the time, over long stretches. That is the entire discipline.