It is also interesting to remember that the web standards movement, led by many including the illustrious JeffreyZeldman, started for a concern with accessibility of trying to make sure that the internet was usable by all, despite cognitive or physical limitations.
The web standards movement, led by JeffreyZeldman and others (great interview with Zeldman here, on The Great Discontent), paved the way for the large chunk of app development that can now be done in HTML 5, CSS3 and JavaScript and work on all platforms.