Well…this is just my opinion so anyone can feel free to counter. but the word was originally a negative word that was used to degrade people who were the descendants of African Americans. It is still used as a degrading word. However, the black hip-hop community has taken the word and changed the spelling(‘nigga’) and have created a new meaning of endearment. they feel by taking away the negative connotation of the word, it will not have such power in the black community. however, the word is still not to be used by non-blacks, because of its history.