Imagine someone in a wheelchair not being able to go to the local public library, because there were no access ramps at the entrance. You would be outraged, right? In a modern, inclusive society, we have come to expect entrance ramps (or a viable alternative) enabling access to public buildings. Now we must expect the same when it comes to public information. Creating accessible content is the digital equivalent of adding ramps, disability toilets and good signage to physical buildings to improve access for all.
To celebrate Global Accessibility Awareness Day 2015, FixTheWeb has produced an excellent animated video on web accessibility. Of course, the video is itself a model of accessible media.
Where do you prefer to study? If you work all day at a desktop computer, you probably prefer to study in a different location, different posture. That's easy with Contented courses, now that they're in HTML5 and can be studied on tablets and smartphones too.