The easiest answer to this question is it has to accessible to everyone. Take a look around the next time you’re out and about, what do you see? Smart phones, tablets, handheld gaming devices – this is the mobile age.
It’s important to realize that this is also the age of spontaneous genius. When you had an idea in the 20th century that required some form of research you went home, or went to a library, or looked up companies in a phone book. In the 21st century, we look to our pockets.
With the dimensions of a pocket in mind, we must design websites that look good with limited space. We must also maximize persuasion and minimize frustration. All the effort in the world means nothing if you’re just making people angry.