This site started its public beta in December 2011, it is not a new site and has been running alongside 'Science Fiction & Fantasy' for all that duration, it is not 'splitting off'. Hopefully the site will graduate in due course to become a full stack exchange site - but there is no intention at all to modify the scope of SciFi. I thoroughly enjoy being a contributor to that site.
It is nearly impossible to maintain mutually exclusive scope between Stack Exchange sites. Science Fiction Movies and TV questions are on topic here, other science Science Fiction media, such as novels, short-stories, and comics are definitely off topic.
You might ask "where should I ask Science Fiction or Fantasy questions"? The answer depends on whether you think the question is better answered by the community here, or there, (or both). Personally since I am passionate about developing this community, I would encourage you to post here if it is at all appropriate!