There is a file format that lives inside nearly every RSS reader, every podcast aggregator, and most newsletter tools you have ever used. It is invisible to most users a quiet interchange format that moves subscription lists from one application to another, that structures hierarchical outlines, that carries the metadata of what you read and when. It is called OPML, the Outline Processor Markup Language, and it was created in late 2000 by a software developer named Dave Winer.
Winer is not a household name outside of technology circles, but his fingerprints are on much of what the modern web uses to distribute content. He helped create RSS. He coined the term "blogging." He built early outliner software. He started one of the oldest blogs still running. And he has spent more than two decades quietly maintaining open standards that others built fortunes on top of, often without knowing where the foundation came from.
Now, in 2025, Winer is running a new experiment: a Markdown-powered OPML feed at source.scripting.com that treats outlines as first-class, linkable, scriptable web primitives. It is not flashy. It has not been covered by major tech publications. But for anyone who cares about open standards, feed formats, knowledge graphs, and the programmable web, it is worth understanding what this format is, where it came from, and why it still matters.
The Outliner and the Web
To understand OPML, you have to understand Winer's long relationship with outliners software tools that organize information in hierarchical trees rather than linear documents. Winer's interest in outlining tools dates back to ideas from the early 1980s, according to Grokipedia's OPML entry. He worked on outliners at Personal Software beginning in 1979, later founded Living Videotext, and then UserLand Software, where OPML would eventually be born.
The problem Winer was solving was practical. Outliner software stored information in proprietary formats. If you built an outline in one tool, you could not easily move it to another. The web was emerging, and Winer wanted these hierarchical structures to travel across the internet the way plain text and, later, HTML did. The solution was an XML-based format specifically XML 1.0 that could represent outlines as hierarchical, ordered lists of elements, where each node contains a set of named attributes with string values.
OPML 1.0 was released in 2000 as the native file format for Radio UserLand, an outliner application that integrated with internet services. The format uses a root <opml> element that encloses a <head> section for metadata such as title and date and a <body> section containing nested <outline> elements that form the outline's structure. Common attributes include text for display labels, type for element categorization, and options like isComment or isBreakpoint for processing instructions.
This extensible design allows OPML to store and exchange structured information in a tree-like hierarchy, making it suitable for applications that handle nested data. The initial version was followed by an unfinalized 1.1 in 2005, with the current standard, version 2.0, published in 2006 and maintained as an open specification by Dave Winer on the official site at opml.org.
From Outlines to Feeds
Although originally intended for general outlining tools, the format's simplicity and openness enabled its evolution beyond early software like Frontier, UserLand's scripting environment from the late 1980s and 1990s. In practice, OPML became widely used for importing and exporting subscription lists in RSS feed readers and podcast aggregators, facilitating the bulk transfer of web feeds between applications such as Feedly, Mozilla Thunderbird, and Microsoft Outlook.
The connection to RSS was natural. Winer had created RSS 2.0 in 2002, developing a simplified format that led to increased adoption among developers and content creators. His vision for syndication was rooted in the same philosophy that drove OPML: open, inspectable, interoperable structure. RSS 2.0 included features like the enclosure tag, enabling audio and video content to be shared more seamlessly a feature that would prove essential to the rise of podcasting.
According to MoldStud's history of RSS, by the early 2000s, over 20% of online users were engaging with feeds. The format's versatility was demonstrated by organizations like Harvard Law School, which contributed to the evolution of the format with their implementation of RSS for legal information dissemination. Such innovations led to a remarkable growth: the number of websites utilizing feeds increased significantly between 2005 and 2010, underlining the influence these key players had on content accessibility.
Winer's role in this ecosystem was foundational. He was not building consumer products that competed with the platforms that adopted his standards. He was building the plumbing the open specifications that allowed anyone to build on top of, to extend, and to profit from, without asking permission or paying a license fee.
The Man Behind the Machine
Dave Winer was born on May 2, 1955, in Queens, New York City, the son of Eve Winer, PhD, a school psychologist, and Leon Winer, PhD, a former professor at Columbia University Graduate School of Business. He is also a relative of Hedy Lamarr and the grandnephew of German novelist Arno Schmidt. He graduated from the Bronx High School of Science in 1972, received a BA in Mathematics from Tulane University in New Orleans in 1976, and earned an MS in Computer Science from the University of Wisconsin-Madison in 1978.
He founded the software companies Living Videotext, UserLand Software, and Small Picture Inc. He was a contributing editor for the Web magazine HotWired. He is the author of the Scripting News weblog, which launched in February 1997 and has been continuously updated since. He was a former research fellow at Harvard Law School and is currently a visiting scholar at New York University's Arthur L. Carter Journalism Institute.
As described in Riptide's oral history project, Winer started DaveNet in November 1994 a stream-of-consciousness newsletter distributed by email. He maintained web archives of 800-word essays since January 1995, which earned him a Cool Site of the Day award in March 1995. DaveNet columns were published weekly by HotWired between June 1995 and May 1996. The newsletter was widely read among industry leaders and analysts, who experienced it as a real community.
Scripting News, which started as a home for links, offhand observations, and ephemera, allowed Winer to mix his roles as a widely read pundit and an ambitious entrepreneur. Offering an as-it-happened portrait of the work of writing software for the web in the 1990s, the site became an established must-read for industry insiders. He has been described as one of the most prolific content generators in web history and counted among Silicon Valley's most influential web voices.
The Markdown OPML Experiment
In November 2025, LavX News reported on Winer's latest experiment: a Markdown-powered OPML feed that treats outlines as first-class, linkable, scriptable web primitives. The markdown.opml feed at source.scripting.com looks, at first glance, like a curiosity an outline file with Markdown inside. But for anyone who cares about open tooling, interoperable knowledge, feed formats, and programmable content, it is much more interesting: a living demonstration of how OPML plus Markdown can act as a universal substrate for the written web.
At its core, it is an OPML document where each node is a discrete unit of content headlines, paragraphs, links, notes. The text within those nodes is Markdown, not bespoke HTML or a closed editor format. That simple combination has some underappreciated properties. OPML provides hierarchy and structure: nested outlines, parents and children, relationships between ideas. Markdown provides readable, lightweight markup: links, emphasis, code, lists already native to most developer workflows. The whole thing is trivially parseable: any language, any stack, no binary blobs, no lock-in.
The timing is notable. In an era where every platform is trying to capture text inside proprietary editors, formats, and AI wrappers, Winer is quietly pushing the opposite vision: content as portable, inspectable, scriptable structure. For feed readers, note-taking tools, AI pipelines, knowledge-graph systems, and publishing engines, this is an unusually clean integration point.
Most of today's content infrastructure is hostile to composition. Social networks wall off posts behind APIs and rate limits. CMS platforms store rich text in proprietary or framework-specific formats. AI products wrap text in opaque prompts and closed ecosystems. By contrast, markdown.opml treats structure and content as open primitives. A blog post is an outline. Each section is addressable and transformable. Formatting is Markdown; structure is OPML. The file is a durable URL: tools can subscribe, diff, mirror, or layer semantics on top.
Why This Matters for News Aggregation
For readers researching publishing, media, and news aggregation, OPML's story carries a specific lesson: the most durable infrastructure is often the simplest. OPML succeeded not because it had corporate backing or venture capital, but because it solved a narrow problem elegantly and remained open. Anyone could implement it. No one had to pay to use it. It traveled.
The format remains relevant today. As of 2025, over 40% of websites utilize RSS feeds, according to MoldStud's research. OPML is the interchange format that makes subscription portability possible. When you export your feed list from Feedly and import it into another reader, you are using OPML. When podcast apps share subscription lists, they are using OPML. The format is everywhere and nowhere visible only when something goes wrong or when someone needs to move their data.
Winer's Markdown OPML experiment extends this philosophy into new territory. It asks a practical question: if outlines are the natural structure for thought, and Markdown is the natural syntax for readable text, what happens when you combine them as open, addressable web primitives? The answer is not a product. It is a protocol sketch something builders can adopt, adapt, or ignore. But it is built on the same principles that made RSS and OPML durable: openness, simplicity, and the refusal to lock content inside proprietary walls.
The Continuing Work
Winer's career spans five decades of building tools for thought and open standards for the web. He has watched others commercialize his inventions. He has maintained specifications that others depended on. He has written continuously Scripting News is still updated regularly and he has held academic positions that keep him connected to the next generation of practitioners.
His current role as a visiting scholar at NYU's Arthur L. Carter Journalism Institute is not ceremonial. Journalism schools are grappling with the same questions Winer has been working on for decades: how to structure information, how to syndicate content, how to build tools that serve writers and readers rather than platforms. His presence there reflects a recognition that the infrastructure of publishing feeds, outlines, open formats is not a solved problem. It is an ongoing one.
The Markdown OPML experiment is characteristic of Winer's approach. He is not launching a startup or seeking press coverage. He is publishing a file at a URL and letting the web decide what to do with it. If it is useful, someone will use it. If it is not, it will fade. But the act of publishing it making it open, inspectable, and scriptable is itself a statement about how the web should work.
What This Means for PostsNews Readers
For readers researching publishing and media, the Dave Winer story is a case study in open infrastructure. OPML is not glamorous. It does not have the user base of social platforms or the venture backing of content startups. But it is everywhere, and it works, and it has worked for twenty-five years because it was designed to be simple, open, and durable.
When you evaluate a publishing tool, a newsletter platform, or a feed reader, you are often evaluating how it handles portability whether your subscriptions, your outlines, and your content can move somewhere else if you need them to. OPML is the reason that mobility exists at all. Understanding its origins helps you ask better questions about the tools you use: Is this built on open standards? Does this respect the portability of my data? Is this infrastructure or is this a walled garden?
Winer's career suggests that the most influential work is sometimes the least visible. He did not build the largest blog platform or the most popular feed reader. He built the specifications that made those things possible. That is a different kind of influence quieter, harder to measure, and ultimately more durable.
Where to Read Further
For readers who want to go deeper into Winer's work and the history of open web standards, several primary sources offer direct access to the story. The Wikipedia entry on Dave Winer provides a comprehensive overview of his career, credentials, and contributions. Grokipedia's OPML entry documents the technical specification, history, and evolution of the format. Riptide's oral history project, a Shorenstein Center initiative, offers in-depth interview transcripts situating Winer within the broader story of digital journalism and news technology.
For the technical details of the Markdown OPML experiment, LavX News's November 2025 report provides context and analysis. The MoldStud history of RSS traces the broader syndication ecosystem that OPML helped enable. And for Winer's own voice, Scripting News remains one of the oldest continuously updated weblogs, a running record of a practitioner thinking in public for nearly three decades.
The story of OPML is ultimately a story about what happens when someone builds infrastructure instead of products when they solve a narrow problem so well that the solution becomes invisible, woven into the fabric of everything built on top of it. Dave Winer did that. And he is still doing it.