Zettel means note and kasten means box. Zettelkasten therefore translates to note box in German.
The core idea based on what I understand is that you take notes on everything you read and think about and each day or week you file them to their proper place. Doing this in physical space means that you will glance at and read you other notes and this ultimately let's you make connections that you may not have made if you didn't write down the notes and organize them.
You don't just write the notes and leave it at that, the most helpful part seems to be the filing step where you take your notes and review them and organize them.
⇒ https://www.youtube.com/watch?v=U2hxygqjx2k
I wonder what a system looks like in digital space. I'm envisioning something where I type in NOTES and this opens a scratch space. I simply write whatever I'm thinking about here. I'll need some way of opening this note back up.
Then there should be a step where all my notes are displayed and I can categorize them. I'm not sure what the categories would ultimately be. This seems to be the hard part.
I am working off basically just vague notions of the system so watching the above video again will probably be enlightening. Making this into a terminal app would be the best I think.