MLK used the term 'black', in place of 'negro' in an effort to equalize our colors. However, he used the term 'negro' much more. He did that because politicians are generally perceived as dumb!(I'm also afraid to say that so is the general population.) So in an effort to promote the much-deserved equality, MLK knowingly contradicted himself so somebody else could continue fighting for equality. This is why we have a holiday for him in the USA. MLK was not only for racial equality, I'd have you know. His ideals represent perhaps 2% of the results of what something like a government census could produce in terms of intellectual morality (now in 2012). Since his time, his actions for improving particularly justice have been ridiculed through means of lust and entertainment by mostly greedy people. See, the sad part is that people are not naturally racist by any means. I'd give it to you to say that there are indeed a few who are true bigots. Now we are living with an overwhelming 'proud' population of supporters to musical/literary sell-outs, politicians with agendas, personal/corporate/government exploits, and spam-email.
If you are wondering why there has not been any significant revolutionary achievement since the era of MLK, you also need to consider asking yourself, "Why are you going to vote for Obama? Negro!"