Zen Coding refers to a neat way to write markup quickly.

The following blogs provide summary and examples:

http://www.456bereastreet.com/archive/200909/write_html_and_css_quicker_with_with_zen_coding/

http://mondaybynoon.com/2009/08/17/the-art-of-zen-coding-bringing-snippets-to-a-new-level/ (skip the cruft about snippets)

Emmet

Zen Coding has been renamed to Emmet and includes an expanded feature set. See Shin Aoyama’s Github page for a fork of Ron’s repo that includes new Emmet features.

zencoding-mode

A minor mode providing support for Zen Coding by producing HTML from CSS-like selectors. Example:

a.x>b <a class= "x" ><b></b></a> a#q.x>b <a id= "q" class= "x" ><b></b></a> a#q.x.y.z>b <a id= "q" class= "x y z" ><b></b></a>

Ron Panduwana is the current maintainer.

See the Github page for guide/installation instructions.

YouTube video

See the page history for early developments/discussion on this mode.