Well, as far as Walter Cronkite in relation to the outside world goes, I assume you've heard of the Vietnam War. Cronkite rarely, if ever, made his personal opinions known, but around 1968-9 he decided to do an editorial on his broadcast stating his opinion that the war was unwinnable, and that the U.S. should withdraw. As "the most trusted man in America", this swung mainstrean opinion against the war more effectively than perhaps all the previous anti-war protests put together.
So, in response to "Who is Walter Kronkite (sic) in relation to the World outside US television?", I'd say he was a pretty significant person, whether you know his name or not.
Dale