Read this book. The author's basic argument is that the way humans think has been shaped by technologies we've invented like alphabets, the map, the clock, and the book. The book encouraged a kind of deep, contemplative, and imaginative thinking that had an immensely positive effect on human society (especially after the printing press was invented), but it is now being supplanted by computers and the internet, which encourage a kind of scatter-brained, unfocused mode of thinking by their very design.
You had the same problem before with TV, radio, videogames, etc but to nowhere near the same extent because none of them could display text the same way computers can, so none of them could replace books.
Since reading it a week ago I think I must've spent a sum total of 20 minutes on chans, down from probably 8+ hours a day of endless F5'ing in one window while watching something else in another.