computer based learning and LearnNext

I have just purchased a computer based elearning product called LearnNext.com. I got to know about it after reading about it on this site (Mr pedagogy's article). It is really very useful, and everything is explained amazingly well. I wanted to ask other people here if they have used any such elearning product, and have they been good. i am wondering why such useful things are not available more publicly, and more students know about it