Gary Illyes from Google said last night at SMX Advanced that you cannot optimize for RankBrain and there is no RankBrain score.
So Danny Sullivan grilled Gary Illyes last night on what that means. If it is a query interpretation, then it is about understanding the query, it doesn't re-rank search results. But Gary said "I am going with the previous Google messaging" and he called it a ranking signal.
So Danny grilled more and Gary said, unlike other ranking signals like Panda, page speed and others - your site/page is not assigned a score with RankBrain. He also added, I know you want me to tell if how do you optimize for it and you can't optimize for it Gary said.
Here are some tweets from the coverage of those remarks:
All of this really makes me think, Google is calling it a ranking signal but it really doesn't act like any other ranking signal Google has. So maybe it isn't really a ranking signal.
You can watch the live 1 hour video, which is a lot of fun, on Search Engine Land's Facebook page.
Forum discussion at Twitter.