SuperNotecard is an intuitive tool that uses notecards to capture and organize your ideas. These virtual notecards can be moved into decks, arranged on the screen, or grouped and categorized with ease."
In other words, it does what StickySorter does, and then some. It's a very competent application. I tried this program out a long time ago, but it did not convince me as an application for nonfiction writing (for which, to be fair, it was not designed either). I should have mentioned it a long time ago.
Other so-called "writing applications," like Scrivener, use the notecard metaphor in more limited ways, i.e. the actual writing is not done on the "notecards," but in documents. The notecards are for meta-information about these documents. I must say that I like this approach better.
In the end, I prefer, of course the wiki or hypertextual approach, which is less visual, but much more flexible and conceptually "cleaner." In the final stages of writing and note-taking, an outline is just as good or better than "fake" or virtual cards. In the early stages of writing (where one does not yet know where one is going or what one will ultimately say), even an outline gets in the way—or so it is for me.
1. Another thing I did not like was that it is a Java application. (I know this is a highly subjective reason, but I avoid Java where I can.) It is available not just for Windows, but also for the Mac and Linux.
2. See also Virtual Notecards.