How are they similar? That link goes to a bookmarklet that lets you drag letters apart to produce a stylesheet adding extra margins to those letters. This story's link goes to a JavaScript library that provides a dozen new CSS rules for selecting and transforming words and letter spacing, rotation, color...

In this way "kerning.js" doesn't seem to be the most descriptive name for this project. Everything but the first example is not related to kerning, just typography. My first thought, when I read the title of this post, was "but we already have kernjs..."