Web apps were also very useful for learning JS and browser APIs, before everybody started minimizing and obfuscating it. I learned how to write a rich-text editor just by looking at the code of Hotmail's email editor.
Fair enough, but think of that free and open stack: (layer 1), Ethernet, IP, TCP/UDP, HTTP/SMTP/DNS/etc, HTML/JavaScript. How many cut their teeth on those?
The apps on top, Facebook, Snapchat, etc., are not so open and much of what they do is out of reach from the user.
Also, I meant to add above: People could tinker with data files (e.g., Word docs), configurations, etc. The whole system was local and accessible. You could write local code, such as VB or for Windows, that integrated with those systems.
