Some of my first posts dealt with Daniel Luedecke's Zettelkasten. I criticized that entries in the program could be associated only through keywords (and that this was not how Luhmann's Zettelkasten worked). This has changed in the intervening years. I just read this reaction by one of the users of the program on Luedecke's blog: "The advantages of your program consist in its ability to link entries directly and freely; and not of entries in their entirety, but of the concepts and ideas found in them." [Die Vorteile deines Programms liegen für mich in der Möglichkeit der direkten, freien Vernetzung (nicht von den Zetteln als ganzen, sondern von Begriffen und Ideen in diesen Zetteln).]
If I were to decide now what program to use for my "external memory," "Der Zettelkasten" would be a much more serious contender. As it is, I am committed to ConnectedText. Der Zettelkasten is a very capable program, and many of you may really benefit from using it. The entry is in German, and the fact that the program (and most of its users) are German may present a problem for some, however.
1. I am not here going to discuss the details of the suggested approach.