The N word is taboo among polite society, and that is why instead of "nigger" people use the silly euphemism "the N word." Nigga, nigger, niggar refer to a black person. I suppose this is so because black people react violently when they are addressed as "niggar". If they did not react, whites would probably stop calling them "niggars" and would have to find another word.
Blacks call whites "kraka", and whites feel insulted by the term. I sort of like it myself. Most of my friends are krakas and they are all right, most of them.
YOLO is a new acronym used on the internet, mainly by those who are still wet behind the ears, and it means You Only Live Once. It is used to justify whatever one does because, after all, we only live once, so what the hell!