Moocs have existed since the late 1800s but grew significantly starting in 2011-2012. They allow for open access to education across universities and have various structures including many-to-many interaction and peer assessment. Popular MOOC platforms that provide free courses include edX, Coursera, Udacity, iTunesU, Yale Open Courses, and Harvard Extension School. They provide benefits such as advancing learning, sharing information across universities, and increasing access to educational resources and technology.