1) "Nigga" and "Nigger" are two completely different
words, said with totally different contexts. NEVER say Nigger, CAREFULLY say Nigga.
2) In the modern
day, almost everyone (of different races) casually says "nigga" amongst their closest
friends. If you are MY nigga - that means you are one of the most loyal, trusted, dependable, needed friend I have. If you are just A nigga (not my friend) then most likely you are either being funny, foolish, ghetto, cheap, or overly confident in a social context.
3) People should
stop saying "nigga" after they stop seeing one... which will probably never happen.