Just came across this item <https://blog.archive.org/2017/08/11/hypercard-on-the-archive-celebrating-30-years-of-hypercard/> at archive.org about an online emulator that runs HyperCard stacks. HyperCard, in case you didn’t know, was an application created by Apple Macintosh engineer Bill Atkinson for that platform in 1987, and it was always hard to describe exactly what it was for. But it allowed users to create their own applications, aka “stacks”, around a card-based paradigm. One of the commenters points out that the basic idea is still alive and well, in the form of LiveCode, which is available as a paid online service <https://livecode.com/> and also in the form of Free Software <https://github.com/livecode/>.