Markdown, the WD-40 of Digital Information
Markdown has barely changed in twenty years while everything around it was rebuilt. That's not luck. It's what happens when a format finds the exact sweet spot between content and meaning.
There is a can of WD-40 in almost every workshop in the world. It doesn't do any one thing brilliantly. It loosens, lubricates, displaces moisture, protects against rust. It works on hinges, bolts, zippers, bike chains, garden tools. The reason it's everywhere is not that it's the best at anything. It's that it's useful for almost everything, costs almost nothing, and leaves no mess.
Markdown is the WD-40 of digital information.
Just enough structure
John Gruber published the original Markdown specification in 2004. The idea was simple: a plain text format that reads naturally as text but converts cleanly to HTML. A # becomes a heading. **bold** becomes bold. A blank line between paragraphs is a paragraph break. No tags, no toolbars, no proprietary file format.
Twenty years later, the spec has barely changed. The software around it has been rebuilt dozens of times. The platforms it feeds into have come and gone. Markdown itself just kept working.
That persistence is worth examining. It's not inertia. Rich Text Format persisted for decades out of inertia, dragging its bloated XML through every Office suite until it quietly died. Markdown persisted because it kept finding new uses its creator didn't anticipate.
The reason is the sweet spot it occupies: between content and meaning.
Content and meaning
Most formats choose a side.
HTML carries meaning but not content: the tags tell you what something is, but the structure is invisible to casual reading. A human can read raw HTML, but it requires effort. The format is for browsers, not people.
A Word document carries content but obscures meaning: it looks right on screen, but extract the text and the structure collapses. Headings become large bold text. Tables become chaos. The meaning was in the rendering, not the file.
Markdown carries both, lightly. A heading is marked as a heading, not just styled to look like one. Emphasis is marked as emphasis. A list is a list. But the markup is so minimal that a human reading the raw file sees structure without syntax noise. The # before a heading reads almost like an underline. The ** around a word barely interrupts the flow.
That dual legibility is the trick. A human reads it as text. A machine reads it as structured data. Neither has to compromise.
https://hoeijmakers.net/the-wd-40-of-digital-information.md
Where it keeps showing up
GitHub made Markdown the default format for READMEs in 2009. Not because it was mandated, but because developers were already using it in plain text files and it rendered cleanly. Stack Overflow adopted it for questions and answers. Notion built an entire productivity platform around it. Obsidian turned it into a knowledge management system. Slack, Discord, WhatsApp: all support some dialect of Markdown for message formatting.
Every time a new context needed lightweight structure, Markdown was already there.
AI systems followed the same logic. Training data in Markdown is cleaner than HTML: no scripts, no navigation chrome, no cookie banners embedded in the text. The structure survives the extraction. A heading in Markdown is still a heading after ingestion. That's not true of most formats.
When AI assistants started browsing the web and retrieving content for users, Markdown became the preferred output format for responses. Not because it was specified. Because it was the format that travelled best between systems.
A deliberate experiment
A few weeks ago I added something to this site: a Markdown copy of every post, served alongside the HTML version. A path like /this-post.md returns the same content as /this-post/, but as clean Markdown text. I also added an llms.txt file indexing all of them, a signal to AI systems that structured content is available here.
The experiment was modest. Serve the content in the format machines prefer, see what happens.
What happened was immediate. AI crawlers found the .md paths within days. ChatGPT-User, OAI-SearchBot, and others started reading through them systematically. And when a swarm of scrapers hit the site recently, 202 of their 400 requests in a single minute were for .md paths. They didn't find those endpoints by accident. They went looking for them, the way you go looking for the WD-40 when something needs loosening.
The Markdown layer attracted exactly the traffic it was designed for. The format did the work.
Why slim formats win
RTF tried to carry everything. SGML tried to define everything. Both are essentially dead for everyday use. The formats that survive are the ones that carry just enough.
Markdown carries hierarchy, emphasis, links, code blocks, and lists. It leaves everything else alone. That restraint is what makes it composable: you can feed it into a static site generator, a documentation tool, an AI pipeline, a note-taking app, a chat interface. It doesn't arrive with requirements. It arrives ready.
The web itself works this way. HTTP is a slim protocol. HTML, at its core, is a slim format. The richness came later, layered on top. The slim foundation is why it all still runs.
Markdown found its sweet spot and stayed there. Two audiences, one format, twenty years, no mess.
That's not luck. That's the point.
Rob Hoeijmakers
Rob Hoeijmakers