Obsidian

The anti-Notion. Obsidian stores everything as local Markdown files on your device — no cloud lock-in, no subscription required for core features, no risk of a company going bust and taking your notes with it. The bi-directional linking and graph view create a "second brain" where notes connect to each other organically. The plugin ecosystem (1,800+ community plugins) rivals VS Code's. Obsidian has grown to 4+ million users without venture capital, proving that privacy-first, local-first software still has a massive market. The paid sync ($8/mo) and publish ($16/mo) services fund development.