I’m a huge fan of Niklas Luhmann (a sociologist with a system theoretic approach who organized his research with index cards in a gigantic Zettelkasten – which roughly translates to box of paper slips), so I was delighted to stumble upon zettels

Zettels is a personal web memo note box – easy to use, fast and reliable. All your ideas and notes are saved on notes in Zettels. You maintain the overview. You have access to your notes from anywhere…

There is no shortage of note taking, idea drafting, or brainstorming apps around, but this one is quite charming.