A Massive Open Online Course (MOOC) is an online course that allows unlimited participation and open access via the web. The first MOOCs emerged from the open educational resources movement in 2008. There are two main types of MOOCs - cMOOCs which focus on connectivist and constructivist approaches, and xMOOCs which are more formal and behaviorist. MOOCs allow anyone with an internet connection to participate in online learning regardless of age, ability, or location. However, they also face some criticisms like low completion rates and requirements of self-regulation from participants.