A Social Filesystem
January 18, 2026
Remember files?
You write a document, hit save, and the file is on your computer. It's yours. You can inspect it, you can send it to a friend, and you can open it with other apps.
Files come from the paradigm of personal computing.
This post, however, isn't about personal computing. What I want to talk about is social computing--apps like Instagram, Reddit, Tumblr, GitHub, and TikTok.
What do files have to do with social computing?
Historically, not a lot--until recently.
But first, a shoutout to files.
Why Files Are Awesome
Files, as originally invented, were not meant to live inside the apps.
Since files represent your creations, they should live somewhere that you control. Apps create and read your files on your behalf, but files don't belong to the apps.
Files belong to you--the person using those apps.
Apps (and their developers) may not own your files, but they do need to be able to read and write them. To do that reliably, apps need your files to be structured. This is why app developers, as part of creating apps, may invent and evolve file formats.
A file format is like a language. An app might "speak" several formats. A single format can be understood by many apps. Apps and formats are many-to-many. File formats let different apps work together without knowing about each other.
Consider this .svg:
SVG is an open specification. This means that different developers agree on how to read and write SVG. I created this SVG file in Excalidraw, but I could have used Adobe Illustrator or Inkscape instead. Your browser already knew how to display this SVG. It didn't need to hit any Excalidraw APIs or to ask permissions from Excalidraw to display this SVG. It doesn't matter which app has created this SVG.
The file format is the API.
Of course, not all file formats are open or documented.
Some file formats are application-specific or even proprietary like .doc. And yet, although .doc was undocumented, it didn't stop motivated developers from reverse-engineering it and creating more software that reads and writes .doc: