Academic Earth provides videos of lectures by top scholars in "Subjects" that range from Astronomy to Entrepreneurship to Religion, from "Universities" as celebrated as MIT, Berkeley, Harvard, and Stanford. Visitors must register to view the lectures, but registration is free. There are over 1500 video lectures available, with more being added everyday. In addition to viewing the lectures available by subject or university, visitors can choose by "Instructors" or by "Playlists". When visitors click on "Playlists" at the top of the homepage, they will see a list of lectures by theme, by several different instructors, and a grade given to the lecture series. A good example is the 6-part lecture entitled "Understanding the Financial Crisis" by four different instructors. The series is given a grade overall, in this case, an A-, and when visitors click on "See all 6 lectures" at the bottom of the series' description, they will be taken to the page with the links to the individual lectures, as well as shown the grade given each individual lecture. Visitors can even keep a playlist of their favorite lectures or download the lectures. Visitors should definitely check out the Frequently Asked Questions page, accessible by the "FAQ" link at the bottom of the website.