technique - What is a discovery writer?

From an answer to this question: How do I successfully structure a long fiction piece?

I think I can infer the meaning from the usage but some elaboration would be helpful.

Answer

Stephen King, by my understanding, was a discovery writer. I will paraphrase what he wrote in his book On Writing.

You create some real, believable characters, put them in a challenging situation, and then let them decide where the book would go. If you have done enough work on character development, then your characters should be able to decide how they would act in a certain situation.

The writer should not then try to force the characters to act in the way he would want to act. If the characters you created would want to run away from danger, for example, you should not force them to be brave.

The fun in this approach is that the book can take strange, surprising turns, which can surprise both the readers and the author. The disadvantages that I know about are, it is very hard to pull off, and not a good approach if you are under a deadline by an editor.

Also, this approach works well, if like Stephen King, you can easily type 300,000 words for a novel, and then trim it down. If like me, you struggle to reach even the 50,000 of Nanowrimo, this approach will fail miserably.