Emacs support for Jekyll blogs.
If mumamo is present (it's part of nxhtml) then a multi major mode is enabled for the blog posts, so the YAML front matter will use yaml-mode and the chunks between highlight tags also use their modes.
Integrated support for ruby and javascript.
You can add other modes for highlighting in your configuration.
For example:
(add-to-list 'jekyll-modes-list '("erlang" 'erlang-mode))