Yet, reading is not so widespread in our culture as it ideally should be. Reading is a solitary activity. It needs to be inculcated and encouraged in the very young. Most people who didn't grow up with a habit of reading, don't read as adults. Reading books faces stiff competition from television, film, iPads and more. Besides the obvious reasons of increasing your knowledge, bettering your grammar and so on, there are other, subtler reasons that make reading a worthy pastime.
Reading lets you travel. Reading lets you wander and visit places you've never been, it puts you in another person's shoes and increases a feeling of empathy. This is especially true for reading fiction.
Reading increases your concentration. Notice how your concentration and focus is much more scattered when you're online. There are more tabs, ads, links and distractions that keep your mind going everywhere else. Reading a book keeps you absorbed for far longer spells of time, without feeling that weariness which usually accompanies long hours spent on a computer.
Reading books increases your ability to follow longer stories, more complex plots, and more composite ideas. Reading is to the mind what exercise is to the body. Reading lets you develop an appreciation for more layered knowledge.
Reading builds imagination. The building blocks of books are words, and these encourage your mind to create images of places, people, emotions and thoughts. If nothing else, this is by far the most valuable contribution reading has made to humans.
Reading involves understanding of the metaphorical, the non-literal, and often, reading between the lines. In a sense, reading makes you more aware of subtle nuances. Every author writes in a different manner, with different sentence construction and voice. Besides the actual content of what you read, this adds new dimensions to your way of thinking. Reading also helps you become a better writer.
So, read a bit today. And not the newspaper :-)