Vue.JS is a progressive JavaScript framework used for building user interfaces. Coursera's Vue.JS catalogue teaches you about this adaptable ecosystem which scales between a library and a full-featured framework. You'll learn to create dynamic User Interfaces, single-page applications, and complex web interfaces. You'll delve deep into the Vue.js ecosystem, covering concepts such as Vue CLI, Vuex, Vue Router, and Nuxt.js, as well as learning to integrate and use APIs. This powerful skill will significantly enhance your capabilities as a web developer and broaden your understanding of modern JavaScript web development tools and techniques.