A Digital Garden
I first learned about digital gardens from Maggie Appleton's site, which was also eye-opening for me because of the custom styling. The site didn't feel like any other site. It was the first time I realized that you could just code your own site and that there may be aesthetic or intellectual or other reasons you might want to do that.
I got into Obsidian for note-taking, and quickly stumbled into the personal knowledge management (PKM) community. I was inspired by Nicole van der Hoeven's Fork My Brain, and by Andy Matuschak's working notes.
But a digital garden isn't a "second brain."
For me, it's a place to putter.