A world of words
Udacity is a private educational organization founded by Sebastian Thrun, David Stavens, and Mike Sokolsky, with the stated goal of democratizing education.
Udacity, which started offering free computer science classes in 2011 through Stanford University, currently has six active courses and 250,000 students, a figure which Thrun hopes will be half a million next year.
Students can register in one or more classes before the due date of the first homework assignment. Upon completing the course, students will receive a certificate signed by the instructors.(Wikipedia)