reveal.js was first released in 2011. A few years later I also launched a visual editing environment for reveal.js called Slides (slides.com). It has some pretty unique features targeted at developers, like a built-in CSS editor, access to the HTML source, and stepped line-by-line code highlighting. http://slides.com/news/developers
It’s been really great finding a sustainable way to continue working on open source (reveal.js) thanks to the revenue from the proprietary editor (Slides).