I am having a running conversation on the value of internet/dvd based self defense training with a friend of mine. We both agree that the vast majority of stuff out there is crap, but there also are some gold nuggets to be found in some of this training on dvd, internet, youtube, etc. I would like for anyone, hell everyone, to share with me what it is that would make you purchase a dvd from anyone of the thousands of guys out there offering martial arts, self defense, or combative training. How do you know you are not about to get ripped off by some guy just shoveling crap? Can you actually learn anything that can be physically put to use in a real life situation? What is it that would prevent you buying a self defense dvd online.