Tildes.net

It’s pretty heavily curated, but it’s where I go for non-bot discussion on any variety of topics. Sorted hierarchically, and they keep out the riff raff pretty actively.

The best thing is adding the metadata of a book by ISBN. That or simply search it on worldcat.org and adding by the browser extension.

Phenomenal citations manager.

Academics focused, but Zotero indexing a large cloud storage drive.

Let’s things organized by subject, tag, author, title, or whatever else I want. Also keeps my notes all in one place. Huge huge proponent and it’s open source!