Be Conservative In What You Send. Be Liberal In What You Accept.

Jon Postel was writing about network protocols, but it is really a principle about how to handle the gap between the messy world and the orderly systems we build to operate in it. Wait, that sounds a lot like marketing. Indulge me and consider two places where this shows up:

1. How you take in customer input. Customers don't fill out your forms the way you designed them to.
• They abbreviate.
• They misspell.
• They submit half-finished thoughts in a support chat, leave a review that's really three separate complaints stitched together.
• They respond to a survey with an answer that technically doesn't fit any of your categories.

The instinct in a lot of organizations is to tighten the funnel, require the right format, reject the incomplete submission, force the data to behave. Postel's Law suggests the opposite instinct is usually right. Be liberal in what you accept and build the systems, the forms, the listening posts, so that messy, human, off-format input still gets through and still gets understood. The cost of being strict at the intake point is usually a customer you never heard from and rarely a cleaner dataset.

2. How you ship your brand. The more forgiving you are about what comes in, the more disciplined you need to be about what goes out. A brand that absorbs every channel quirk, every stakeholder's pet phrase, every regional team's local adaptation, and then reproduces all of that variance in its outward voice is incoherent. The teams that manage this well tend to do the reverse by taking wide, forgiving intake and pairing that with a small number of non-negotiable standards for anything that reaches a customer.
• One voice.
• One visual system.
• One set of claims you'll actually stand behind, no matter how many different inputs fed into producing them.

Most marketing organizations get this backwards by first putting rigid intake in front of customers (long forms, narrow categories, "that's not how we track that") and then let output sprawl, because ten different people are allowed to speak for the brand in ten different ways with no one accountable for the through-line.

Way back in 1980, Postel was solving the much narrower problem of how do you get two computers that don't perfectly agree on the rules to still talk to each other reliably. But that's also, more or less, the problem of a brand talking to a market. The world will never send you clean input, and your job isn't to demand that it does. Your job is to be generous on the way in, and disciplined on the way out.

That asymmetry is what durable brands are usually doing, and you should be too.