You can learn at your own pace; and then it's not like when a teacher asks you a question, you get it wrong, then you get embarrassed. Here, the computer asks you and doesn't judge you. If you get it wrong, you just simply go back, learn a bit more progressively; so, it's a very safe way of learning, and yet it's fun at the same time. It's interactive.
Dr Peter Shephard, Ph. D., D. Lit -Leading Authority on the Psychology of Learning