I've made my living writing since the age of 21.  It's just something that I do.  I've often tried to define what it is that makes a writer, but no really clear picture emerges...just snippets and generalities.  A different way of looking at a situation.  Objectivity.  The ability to render thoughts and ideas down to their marrow and pour them before an audience.  Those words capture part of it, but in the end, they just make the definition that much more elusive.