For the longest time, images in the media have depicted nerds the same way. They are portrayed as intelligent yet socially inept, unaware of popular trends, and devoid of any sort of personality. Repeatedly they are made out to be shy and lacking in confidence, which makes them into victims of the "cool" people. These characters are rarely taken seriously in TV or movies, and are present mostly for comic relief or to provide some sort of sidekick for the hipper main character. Although it has historically been an undesirable label, I believe in recent times there has been a...
that is popular culture , so they just acted in a way most comfortable and natural to them. When this behavior was observed by others, the onlookers mocked it, thinking designation as "uncool" might scare them back into conformity. But rather the general attitude was "I'm going to be my own person, and if that makes me a nerd, so be it". The word gradually lost most of its negative connotation. And so it has come to pass over the last few years, people no longer live in fear of the stereotype, but have come to revel in it.