Online journalism encompasses various types of media that have a web presence, including associations, magazines, newspapers, and radio and television websites. There are four main types of online journalism: mainstream news sites that provide editorial content with minimal user participation; index and category sites that offer links to existing news sites and allow for user comments; meta and comment sites that discuss media issues or act as media watchdogs; and share and discussion sites that allow users to exchange ideas and stories. Key characteristics of online journalism include hypertextuality through internal and external hyperlinks, multimediality through the use of different media formats, and interactivity through navigational, functional, and adaptive features that allow users to respond to and customize stories.