At our core, that's what we are - an easy CMS built on top of a responsive framework. But we think responsive design is more than just media queries, it's also about how content affects the browsing experience. A Wordpress theme running Bootstrap may be responsive, but the standard WP content structure is often too clunky on a small screen.

So we're starting with the mobile experience and bringing it to bigger screens. In the process, we learned from our customers that the simpler mobile-first format is particularly suitable for certain small businesses (contractors, restaurants, startups, etc) and lowers their barrier to get online. We'd like to write an article to share our findings!

Sometimes that's all you need.

To be to fair to them, they have added analytics, social integration, SEO optimization, etc.

Disclaimer: I'm working on a service (but targeted at a specific industry) that will offer something similar as a feature but is not the core product/service.