Emphasis Update and Source - NYTimes.com
http://open.blogs.nytimes.com/2011/01/11/emphasis-update-and-source
Last November, I blogged about a few new features on NYTimes.com. Today we’re releasing an update to one of those features, which I’ve been calling “Emphasis”: paragraph-specific anchor links and the ability to highlight text in articles and blog posts.
NYTimes/Emphasis - GitHub
https://github.com/NYTimes/Emphasis
Emphasis provides dynamic paragraph-specific anchor links and the ability to highlight text in a document, all of which is made available in the URL hash so it can be emailed, bookmarked, or shared.
if:book: CommentPress 1.0
http://www.futureofthebook.org/blog/archives/2007/07/commentpress_10.html
"CommentPress, a free, open source theme for the WordPress blog engine designed to allow paragraph-by-paragraph commenting in the margins of a text."