I have always felt that Hypercard is one of the tech world's unsung heroes. It introduced so many of us to the core concepts of the internet before the internet was really a thing. For many people (including Marc Andreesen), their first reaction to experiencing the graphical internet for the first time was "Oh, this is kind of like Hypercard!"
You are missed.
The core concept of Hypercard was the idea of a stack of note cards. If you have ever used 3x5 cards to work on a very large project, you have worked with a real-world version of Hypercard. But Hypercard was so much better because it could perform simple programming tasks, play music and animations, and link cards together via clickable words. It turned a stack of imaginary note cards into a three-dimensional object, and it was incredibly easy to use, to boot.
In a lot of ways, I feel like Hypercard - a 25 year old program that was abandoned in 2004 - is a program whose time has not yet come. It is a program so filled with infinite possibilities that it blows your mind in ways that are difficult to describe. I firmly believe that one day someone will turn to Hypercard for a project that only Hypercard can handle, and in hindsight it will all be so obvious to the rest of us.
My own introduction to Hypercard was via an English Lit class I took in the summer of 1991, in my first year at college. The course was titled something like "Writing In Cyberspace," and was taught by a science fiction author who specialized (at the time) in cyberpunk. He also introduced the class to The Well, which was one of the web's first most primitive forms.
In other words, the whole thing was totally badass.
We were broken into small groups and instructed to create a literary work in Hypercard. I did a terrible job with my part of it. The barest bits that I remember still make me cringe at the thought of it. But the experience of learning how to use Hypercard, of creating my own non-linear narrative, was mind-blowing in a formative way that I have rarely experienced before or since.
R.I.P. Hypercard. You are missed.