Seconded. I’m not terribly happy it’s closed-source, but the team seems quite ethical in their approach to software development and user privacy, and for anyone not in the know about Obsidian, the big highlights that still make it worth it for me are:

• Markdown formatted notes (standard format you can port across many different kinds of apps, especially useful as an exit strategy if Obsidian ever enshittifies)
• Plugins & Themes (Add basically any arbitrary functionality or looks you need, from structured query languages to analyze your notes, to automatic image format converters)
• Note Linking (being able to link your notes like so: [[Name of Note]] (shows as Name of Note in reading mode) so you can easily structure your knowledge, and build relationships between notes

Also now free for commercial use!

I’m also a big fan of Obsidian.

I am a happy MediaWiki user and it’s FOSS.

And with Obsidian I still own my files, which are just in markdown and can be read by literally any other program.

Same. Although I’d love a fully open source, non-electron alternative.