Ruby is an interpreted, dynamically typed programming language designed for simplicity and productivity. It has gained widespread adoption among startups and large companies for building web applications using Ruby on Rails. Ruby on Rails is a full-stack framework that follows conventions like DRY (Don't Repeat Yourself) to make code efficient and easy to maintain. Learning Ruby and Ruby on Rails provides advantages in today's job market, and resources for learning include CodeAcademy, online forums, and collaborative programs like Microverse which provides support and community.