It is possibly this:
http://samuelhughes.com/HNWeb.tar.gzIt got rejected from the App Store.
It tracks unread posts based on your scrolling and highlights new unread posts. It displays web pages in a native browser, makes voting buttons bigger and asks for confirmation, makes the font size appropriate. It works by filtering the HTML that goes to the browser widget, and that aspect of it might need updating if the site's HTML has changed.