Is it just me or was anybody else not sure what Obsidian was while reading this article? The article doesn't explain it at all, so I'm left wondering if I'm incredibly out of the loop or whether this is a very niche thing that I haven't run into yet.
I use it for taking notes, keeping a journal, TODO-list, and to bookmark/annotate stuff. Basically my own personal "knowledge base".
Technology-wise it saves notes as markdown, optionally with a yaml-style frontmatter, built on/with javascript, and exposes a bunch of APIs making it very extensible.
A strength/weakness with it is that it exposes the end-user to all this power, and does not enforce much in the way of ways of working, so you get to define for yourself how you go about using it.
I have mostly settled on workflows that works for me, but it also seems, if I am being completely honest, like there is always some little tweaking/refactoring going on.