After recently mentioning the possibilty of more The Winds of Winter sample chapters (though he thinks he is approaching the limit of what he is prepared to reveal ahead of time), George R.R. Martin surprised everyone today by putting a new chapter online at his website.
Discuss all the aspects of it below. For obvious reasons, the chapter and the discussion in the comments constitute SPOILERS for The Winds of Winter.
The chapter is named Alayne, after the alias Sansa takes on in the Vale.
Consider this a placeholder. Other writers might chime in with their take on it here or in the comments.