The web is not a visual medium
Let me tell you a tale of the web. The story of how it was created as the first universally accessible medium. I am not sure if this is actually what happened. But a lot of things start to make sense if you look at them from this particular perspective.
Birth of a new medium
Our story begins with an old medium: Print. The invention of the printing press around 1440 made books availabe to a lot of people. Scolars like Descartes and Luther published books in languages other than latin so common people could understand them. But what about people who could not read? Simple answer: Someone else needed to read out aloud for them.
Fast forward to 1998. Tim Berners-Lee works with computers. And he is just about to invent the next big step in the evolution of media. With the new technology at his disposal he has possibilities that Gutenberg would not have dreamed of: Documents are made available on a global network, accessible for everyone on the planet. And interactive references known as "links" allow to easily navigate the vast amounts of information.
But there is one more idea that stays in the background. It is rarely noticed, but may be the most ingenious idea of them all: Remember the person who read out aloud? The computer becomes this person. And it does that for everyone, not just for people who cannot read themselves.
Why is that so important? It means that content and presentation are now seperated. It means that computers can produce many different presentations for the same content. They can output a website on big and small screens, braille displays, screen readers or print it on paper. They can be controlled with mouse, keyboard, touchscreen or voicecontrol. Whatever a person needs, the computer can be programmed to provide the right interface.
The dark ages
This could have been a golden age for people with physical or mental disabilities who had had trouble with reading before. The new medium finally promised to given them the support they needed to independently access information. But unfortunately, the idea got lost.
Most people opened their web browsers and were satisfied with what they saw. It was not very different from print and they did not have a reason to ask for more. So slowly, people forgot about the separation of content and presentation. They actually thought that what they saw on their screens was the website, not just one of many possible presentations.
This would hava been fine, except that the people who created websites started believing it, too. They forgot about semantics and only thought about making the content look good in common browsers.
A new hope
In 2007, finally something happened. People started carrying mobile computers with them. These had much smaller screens than traditional computers and were controlled with a touchscreen instead of mouse and keyboard. Of course, most of the recently build websites were not usable on these devices.
The people who made websites had a hard time with this new trend. They soon realized that targeting specific devices would not scale. In a long process of recovery and reinvention, they found their way back to the old idea. And even though these mobile computers are still predominantly used with a screen, we are now absolutely certain:
The web is not a visual medium.