The comments discussion on the topic leaves me sad. And puzzled. There seem to be a lot of whites who are really annoyed that black people are telling them not to use the word. There is another, somewhat overlapping, group of whites who believe it isn't fair that blacks get to use it when they don't. There is a third group, related to the second group, who think the word should be banned, but are mad that blacks aren't setting a good example for the rest of us.
I don't understand this. What makes the word so appealing that removing it from your vocabulary constitutes a major hardship? It's not as if the word itself is so lovely that I long to say it aloud for the sheer joy of its short i's and gutteral g's. I do not think that I have ever found myself saying "digger" or "tigger" aloud over and over so that I could enjoy their sonorous music.
The basic social rule seems to be fairly easy to follow: black people get upset when white people use that word. I am well warned that this is so. Therefore, I do not use that word. I follow exactly the same practice with "dyke", "spic", "guinea", and so forth. And I do not feel that my life has been any less rich because of this forbearance.
If you cannot be happy without a more complex rule, here it is: society has decided that it is a bad thing to denigrate people for their race, gender, religions, etc. Let us assume, arguendo, that society is right about this. Well, when a black person uses that word, it is reasonably obvious that he is not saying "You know what's wrong with you? You're black, that's what's wrong with you". Whereas, given its history, that's a fairly reasonable inference when a white person directs that particular epithet at someone.