Here is an interesting post by Christian Tietze that spells out the main software requirements for the implementation of a Zettelkasten type notes database. This is pretty much how I manage my reading notes these days in ConnectedText. I am really looking forward to reading the software reviews that Christian aims to undertake.
May I humbly point out the post you link to is not by Christian Tietze, but by me?
Hi Manfred, you probably missed the first link (the word “Here”), which does link to Christian’s post first. I did add some titles to the links, so if visitors hover over the links, it will tell them which link is whose. And if not, they can read this exchange… :)