I've found it pretty far from simple. When I was a reporter, people accepted "reporter" as my job title. But after five years of making a living with Web writing, people act weird when I try to explain it. They assume that "writer" means a magazine or book writer.
I do think that money defines the writer. People who don't make money at it can call themselves a writer to themselves, as I did for many years, but when you do make a living at it, you should be able to introduce yourself as such.