The decision to take an online class or a traditional class depends on the person deciding, what it is they expect to get from a class and the type of environment they need to be successful. If you are a student that needs constant instruction and the cracking of the whip from your professor, an online class may not be for you.
The impact of online education is more relevant for the independent student who just needs to be given an outline of the course with the assignments and their due dates to be successful.
The effectiveness of the online class will also depend highly on the type of student that is considering taking an online class. If you prefer a one on one encounter with your teacher and your peers, you may feel isolated while taking an online class.
This may cause you to become bored and in turn not give your all to your class. Or you may find yourself just doing the assignments for the sake of getting them done and getting a good grade and not retain any of the information.