At my company I wrote our internal front-end testing tool (based on the awesome nightwatch.js[1]). We do unit testing with Chrome, Firefox, IE and Phantomjs, but we also grab screenshots at a variety of resolutions, checking all the links and images (not just for working-ness, but also for content), web font rendering, recording performance API data, and more. From their feature list I'd guess bughunt.io is planning something quite similar. This is just an MVP. It's an interesting idea.

[1] nightwatchjs.org