[arinlen]

I feel compelled to mention that Zotero [1] has been around for ages, has clients for most platforms, it's as FLOSS as it gets[2], and you are free to self-host if that's something you'd like.

[1] https://www.zotero.org/

[2] https://github.com/zotero

[jcuenod]

I use Zotero every day, but (1) self-hosting the server is not actually supported and (2) your notes are in a sqlite db.

It is a great tool. I do wish I could self host, though, and I wish the db were just an index of md files (and maybe json for bibliographic details).

[Datenstrom]

Can second this I love Zotero. I only use it for research papers, e-books, and notes about them and I don't use it for personal notes or saving snipits of websites and such but I could see it also working well for that.