Octopress is built on top of Jekyll and is geared towards making blogs to host on Github Pages (they'll run jekyll, but not any plugins, so you need to have a w

Octopress is built on top of Jekyll and is geared towards making blogs to host on Github Pages (they'll run jekyll, but not any plugins, so you need to have a weird deployment setup if you want to use things like Haml and Sass). Jekyll itself is more of the lightweight, no-frills vanilla version.