Things by Dan Sanderson. http://phbt.org/

Scriv2DocBook. A simple workflow for writing technical books in Scrivener, the text composition application from Literature & Latte. The end result is DocBook XML suitable for delivery to a publisher, or rendering into other formats using DocBook tools.

TextCounter. A Chrome extension that adds a character counter to every text field on a page when you click the extension's button. (Proof of concept.)