My expertise is in more of backend development and rapid prototyping. I have been responsible for developing Edupristine's LMS for complete online training.Here are the quora answers which have detailed the LMS : http://www.quora.com/What-are-the-best-examples-of-Moodle-implementationhttp://www.quora.com/E-learning/For-building-a-system-like-Udemy-Coursera-or-EdX-can-one-use-an-available-off-the-shelf-LMS-or-have-this-custom-build-in-PHP-or-Dot-Net(Moodle is the default open source LMS, used by over 75,000 universities and institutions).Also, I wrote automated programming assignment grader and checker in college, which is still being used by Govt of India.