Vue.js enables component communication using event emitters, but as projects grow, managing this through a parent component can become cumbersome. An event bus in Vue.js allows direct communication between components without involving a parent, using a pattern known as publish-subscribe. In Vue 2, developers could implement an event bus using a Vue instance, but in Vue 3, this approach requires an external package like mitt, as the $on, $off, and $once methods have been removed. The event bus, while initially convenient, can lead to maintenance issues, prompting the Vue team to recommend alternatives such as props and events, provide/inject, slots, and global state management libraries like Pinia for more scalable and maintainable component communication. The tutorial explains how to set up a Vue 3 project with an event bus using mitt, and demonstrates component communication through an increment event, emphasizing the importance of understanding various communication strategies in Vue.js applications.