The entire world of education has been undergoing a major change. The idea of attending physical classrooms and lecture halls is falling by the wayside, slowly being replaced by online courses provided by industry professionals and experienced experts.

There are a handful of websites that offer these sorts of classes, but today we're going to focus on three of the most popular and proven among them: Udemy.com (http://www.udemy.com), lynda.com (http://www.lynda.com) and khanacademy.com (http://www.khanacademy.org)