and Wikipedia doesn't necessarily make you smart..
The word "nigger" is an extremely controversial term used in many English-speaking countries, including the United States, United Kingdom, Canada, and Australia (but also in other countries where English is known such as Germany, specifically) to refer to individuals with dark skin, especially those of African descent who previously were racially classified by the term Negro. It was once the standard, casual English term for black people. Associated with the word traditionally have been an often casual contempt, an assumption of inherent inferiority, even of bestiality, making it extremely pejorative.
Historically, African Americans, and others of African descent have appropriated the slur, subverted it to a self-referential term that is often suggestive of familiarity, endearment, or kinship. However, when used in this manner, it is more often "nigga" instead of "nigger". Many, however, always have rejected the term as racist and dehumanizing. Generally, "nigger" is considered a highly offensive racial epithet, especially when used by non-blacks.[1] See the Wiktionary entry for "nigger" for more relating to this
http://en.wikipedia.org/wiki/Nigger