it's not a long story...
One day a web developer wondered if there was any free software that would replace Microsoft's notepad as the default editor for CSS files. As it turns out, there are plenty of free applications that do that. But most had ads all over the place, one crashed the computer, and one had a virus.
So, he decided to start a website that offered an open-source css editor for windows. Enter, snap{css}.
Hopefully more great applications will follow.