Another Zettel-related term that comes up in the quote by Magnus Wieland (in the original German version here) is "Zettelwirtschaft", which is simply translated as "paperwork" in the English translation. Not sure how dictionaries translate this word, but my impromptu translation is "loose-leaf business/operation". It is typically used to describe an unstructured mess of free-floating paper slips, as opposed to a notebook or file folder. My teachers in school have often used it to describe my careless maintenance of teaching material. But like "verzetteln", "Zettelwirtschaft" does not invoke thoughts about note making, only indirectly in the sense that it involves a set of pieces of paper.

I find that last claim highly unlikely. If you walk through a bog, you get bogged down. That's where the phrase comes from, Magnus.