Karate is a traditional Japanese Martial Art system, it breaks down into various individual styles from the same linage. It uses a belt system to indicate seniority levels or 'skill'.
Relationship to Krav Maga
A punch is a punch and a kick is a kick... That is about as similar as Krav Maga gets to Karate. Anyone who studies the styles will know that there are huge variations in punching techniques. The key to Karate is that it works against someone else who is also using Karate, the rigid linear punching is countered by ridged blocks, then it is about skill level in the style. But a trained boxer will ruin a Karate black belt. Karate is now a faded self defence system, it is not going to work in reality, but is is still highly respected as a traditional and sporting style. I was recently challenged about this, with the claim that Chuck Norris does Karate, (he is also a grand master in Taekwondo), and my answer was that remind them that Bruce Lee totally kicked Chuck's arse with Jeet Kune Do, a system based more on reality.