I'm a sucker for productivity systems and setting up software with the promise of getting my life in order. One of those systems is called a Zettelkasten.
I never truly understood the Zettelkasten system until I read this book. It's the perfect explanation of a system that is supposed to help you think.
It's not a system to store your notes. It's a system to connect your ideas.
Very much worth reading if you're into stuff like this.