A discourse community is a group of people who share a set of discourses, understood as basic values and assumptions, and ways of communicating about those goals. Linguist John Swales defined discourse communities as "groups that have goals or purposes, and use communication to achieve these goals.". Discourse communities can be found in various settings, including academic journals, email lists, online forums, workplaces, and recreational groups. Each discourse community has its own set of written or unwritten rules about what can be said and how it can be said. John Swales outlined six defining characteristics of a discourse community: common public goals, methods of communicating among members, participatory communication methods, genres that define the group, a lexis, and a standard of knowledge needed for membership. Discourse communities can be viewed as social networks built from participants who share some set of communicative purposes.