To make generalizations, you may be an extrovert and the prior poster an introvert.
Extroverts tend to communicate best by voice. Introverts, in contrast, tend to communicate better in a written medium.
Now, to show my bias, I perceive extroverts as people who never shut up and apparently lack an inner voice -- because all they do is unleash an unending, unfiltered stream of verbal garbage when they 'think aloud.' They bombard you with one idea after another without waiting for consideration or response. Even something as simple as, "Hey, how are you doing?" before they launch into their spiel. If you asked, why didn't you wait for a response?
Introverts, in contrast, tend to internalize and hash over a response before they commit it to the outside world. They think more about precise and appropriate wording. They don't respond as quickly, but they typically respond after giving due consideration to the question.This lends itself best to writing, where they can take the time to formulate their thoughts. An introverted friend of mine once commented that extroverts "are impatient and do everything and half-assed."
Introversion has nothing to do with shyness, although the two are more common together than with extroversion. Really, introversion and extroversion deal with how people receive and process information.