Learning MA on the internet

So here is another question, im sorry i ask so much. Is it possible for anyone to learn martial arts thru the internet? Before i started practicing taekwondo, i watched a lot of taekwondo tutorial movies by kwonkicker. And to be honest, sometimes i forget what he tells in his tutorials, but he explained me how to do the spinning hook kick better then my master. And not to mention even my master himself told me to look at the poomsaes on youtube, to practice it at home.



But i remember at my boxing gym, there was a guy who said he watched some tutorials when my coach asked him if he has ever done some boxing before. And my coach laughed, saying you cant learn martial arts from the internet. And ofcourse it turned out the things he had 'learned' went in vain. He never returned either, but yeah. But is there anyone who learned and mastered a lot by the internet? I would really appreciate if you answered honestly without giving false hope. And ofcourse thanks in advance.