It seems like this is more of a workflow than just a framework. Zurb and bootstrap don't come with build tools as far as I know, whereas this includes a gulpfile and a bunch of other stuff that's very common in my workflow. This feels more yeoman-esque + generator to me.

Edit: Totally posted this before I read 'Web Starter Kit is inspired by Mobile HTML5 Boilerplate and Yeoman's generator-gulp-webapp, having taken input from contributors to both projects during development. Our FAQs attempt to answer commonly asked questions about the project.'