Not to be pedantic or anything, but git != github.
AFAICS, none of this is about github. It's about git, the protocol, the versioned object store and markdown, the markup layer.
AFAICS, none of this is about github. It's about git, the protocol, the versioned object store and markdown, the markup layer.
Plus it's easy to host the HTML output of your books on GitHub thanks to their brilliantly simple gh-pages service.
So that's why GitBook is also about GitHub.