But yes. And I kept this article non-technical. But the frameworks that exist are overwhelming sometimes; there's QUnit, Jasmine, Mocha, Chai, Gulp, Grunt, Webpack, Less, Sass, Stylus, CoffeeScript, Babel, Typescript.
These do mostly similar things but each company you work for uses something else and has their own writing styles, architecture and whatnot.
Difference between a 50th-percentile and 99th-percentile front end developer is very visible to users and has a direct effect on user adoption / retention.
Had some success with the Music Player for Reddit (http://reddit.musicplayer.io/) this year. Received good feedback from Reddit, Product Hunt and The Next Web. I'm not doing this for profit so I only have about three figures in donations coming in which cover the hosting and domain name costs.
One of the best in my opinion. I use it for literally everything. It's really versatile in the way that it doesn't force you to use templates.
The new beta (http://beta.semantic-ui.com/) version looks really promising as well, it's made to work with themes but it's a different way of working than the previous version. You get more control in building from less.