Hypermedia is a style of organizing and accessing information through a network of multimedia nodes linked together. It extends the concept of hypertext by allowing links between different media types like sound, video, and virtual reality. Some key features include hypertext links within and between documents, interactive forms, tables, graphics, and links that connect various media to provide an interactive learning experience for students. Both advantages like facilitating creative and individualized learning, and disadvantages like potential for confusion and skipping elements, are discussed.