Ferdelance

What do you forum members think of Bruce Lee's "One-inch Punch?"
Was it hype,or is such a thing possible? If is is possible, I would like to know from someone who knows:
1.How do you develop such a thing, and,realistically speaking, how long would it take, training on a regular basis?
2.If it is real, why isn't it more commonly employed?
Sincerely, Ferdelance