Thousands of pieces of free educational material — videos and podcasts of lectures, syllabuses, entire textbooks — have been posted in the name of the open courseware movement. But how to make sense of it all? Businesses, social entrepreneurs and "edupunks," envisioning a tuition-free world untethered by classrooms, have created Web sites to help navigate the mind-boggling volume of content. Some sites tweak traditional pedagogy; others aggregate, Hulu-style.

Academic Earth

Richard Ludlow started the nonprofit Academic Earth two years ago after M.I.T.'s OpenCourseWare helped him pass linear algebra as a Yale undergraduate. His site offers the courses of 10 elite universities — 130 full courses and more than 3,500 video lectures. Viewers can turn the tables on professors and grade courses. Other guidance includes "Editor's Picks" and "Playlists," lectures selected around a theme like "First Day of Freshman Year" and "You Are What You Eat."

Connexions

Connexions, started at Rice University 10 years ago, debundles education for the D.I.Y. learner. Anyone can write a "module," the term for instructional material that can be a single sentence or 1,000 pages. Connexions hosts more than 16,000 modules that make up almost 1,000 "collections." A collection might be, say, an algebra textbook or statistics course.

The service generates 70 million to 80 million page views a month, according to its founder, Richard G. Baraniuk. Readers can contact module creators with feedback or, because these are not immutable textbooks, to suggest edits. "The whole idea is to grease the wheels to make content up to date and correct," Mr. Baraniuk says. Teachers, for instance, can re-work examples and exercises, then republish the textbook for their own students.