What Email Got Right
Email has outlived every tool that tried to replace it. The reason isn't habit or network effects. It's the schema.
In 1971, Ray Tomlinson sent the first email — from one terminal to another sitting in the same room, just to see if it worked. He later admitted the message was probably "QWERTYUIOP" or something equally forgettable. But the infrastructure underneath it wasn't throwaway. RFC 822, published eleven years later in 1982, formalized the schema that would govern every email sent afterward: From, To, Date, Subject, Body. Five fields. That's it.
That schema is why email is still here.
The knowledge base nobody uses intentionally
Most people who use their inbox as a knowledge management tool don't think of it that way. But consider the behaviors: you forward yourself an article to read later. You email a colleague a decision you want on record. You search your sent folder for what you agreed to six months ago. You've probably got threads that are effectively project notes — a chain of replies where the most recent message is the running summary of everything that came before.
This is personal information management. Steve Whittaker, a computer scientist who spent decades studying how people handle digital information, documented this pattern in his 2011 review of the field: email functions not just as a communication channel but as a de-facto task list, filing cabinet, and shared memory system. People don't do this because email is a good knowledge tool. They do it because email works, and it's always there.
The question is why it works when nearly everything else doesn't.
Schema as survival
Google Wave launched in 2009 with a full conference keynote, a waiting list, and genuine excitement. It was supposed to replace email — a real-time, collaborative system where conversations and documents lived in the same place. It was shut down in 2010. Google Buzz, Google+, Facebook Workplace, Microsoft Yammer: the graveyard of email killers is long and well-populated.
Email survived all of them for one reason that almost nobody cites: it has a schema, and that schema is defined by an open standard that no single company controls.
RFC 822's five fields mean that a message created in 1988 can be read by any email client built in 2025. You can export your Gmail as a standard MBOX file and open it in Thunderbird, Apple Mail, or a Python script you wrote yourself. The format is documented, stable, and not owned by anyone. Slack's export is proprietary JSON that Slack can change at will. Notion's export is tangled Markdown with inconsistent formatting. Evernote's ENEX format is XML, but good luck doing anything useful with it outside of Evernote.
The schema isn't just about portability. It's about what becomes possible when every tool handling the data knows what shape the data is in. Spam filters work because they understand the From field. Search works because every email has a Date and a Subject. Threading works because clients can group messages by a shared identifier. The five fields in RFC 822 are the reason the entire email ecosystem exists.
The shape of a note
Personal knowledge tools have no RFC 822. A note in Notion is different from a note in Obsidian is different from a note in Apple Notes. They're all blobs of text with a timestamp and maybe a title. That's not a schema — that's a file. And when tools treat knowledge as files rather than structured records, the result is always the same: full-text search, which means you can only find what you remember to search for.
The exception is the piece of knowledge software that has lasted longest: the to-do list. Tasks have a schema. Status (done or not), description, due date, assignee. That fixed shape is why task management software can be imported, exported, and migrated more reliably than notes. It's why tasks in one app can sync with third-party clients. The schema did it.
People have a natural schema too: name, contact details, relationship history, notes. The reason contacts apps are usable while notes apps are graveyards is the same reason email is durable. Structured data ages better than unstructured data. The fields don't decay. The relationships don't disappear when you change tools.
What survives
If you're choosing among personal knowledge tools, the schema question matters more than the UI. A tool that stores your knowledge in an open format with a defined structure is making a fundamentally different bet than a tool that stores it as a proprietary blob. The former accumulates value over time. The latter holds you hostage.
Email made the right bet in 1982, more or less by accident. The designers of SMTP and RFC 822 weren't thinking about longevity — they were trying to get a message from one machine to another. But the schema they wrote down has outlasted every system that tried to replace it, because open structures can be built on and open formats can be read by anyone.
Your notes don't have to work like email. But they could probably learn something from it.
Asgeir Albretsen is the founder of Harbor.