With increased demands for online courses, instructors are challenged to facilitate discussions that promote critical thinking and mastery of content. Synchronous and asynchronous discussion forums are used to create a Community of Inquiry (COI) across four respective disciplines and areas: English as a Second Language (ESL), Teacher Education, Industrial Technology, and Human Resource Development (HRD). Understanding the benefits and limitations of each forum and their applications allows instructors to facilitate quality online discussions that foster development of social, cognitive and teaching presence.