The "asdfkasjdf;lakjsdfkjasdf" is a means of expressing one's self in ways that words cannot; especially over the internet in which words and exclamation points only hold so much meaning. As it is written in chapter three of Ecclesiastes that "there is a time for everything," there is also a time for the keyboard spaz.
In short, the meaning of the keyboard spaz is specific to its use/context, but its true meaning is far more profound. It is a communication between sender and receiver in which the receiver effortlessly intuits the intended meaning. This sacred form of communication runs deep in the intuitive connection between two like-minded people.
Friend: "Right?! 'Holy shit' were my thoughts exactly!"
This, is the sacred Keyboard Spaz.
Person 1: Did you hear? Someone baked a 400 pound brownie!
Person 2: 823yu4iwhjfkfisdhsadknf;sdjfhoasuidfhsa REALLY?!!!??!!?!!?!
Person 1: Keyboard spaz much?