It is true Marcia, that self-discipline is an essential ingredient to successful online learning . As a matter of fact, self-discipline leads to success in other areas of our lives.
Some argue that in an on-the-ground setting we cannot cater to learners' preferred styles of learning—a goal not easily achieved in an online setting when one considers some unavoidable constraints that are usually placed on course development—funding and time being the two most predominant. Yet, students have had tremendous success in online learning environments.
In an online environment, there is more time and more opportunities to express, share, and evaluate ideas particularly through asynchronous discussions than there is in a typical classroom environment.
In conclusion, once students have the requisite skills necessary for participating in learning online, I believe they would learn just as much or even more in an online environment than in a traditional classroom setting.