Ethan Zuckerman, who founded the GeekCorps org that works to help bring tech to Africa, has created a call-to-arms for the free, collaborative Wikipedia encyclopedia to address its systemic bias towards subjects of interest to white, Anglo-American nerd-boys, expanding its net to cover things like the Congo Civil War, nursing, and agriculture.
Wikipedia is biased toward over-inclusion of certain material pertaining to (for example) science fiction, contemporary youth culture, contemporary U.S. and UK culture in general, and anything already well covered in the English-langauge portion of the Internet. These excessive inclusions are relatively harmless: at worst, people look at some of these articles and say "this is silly, why is it in an encyclopedia?"
Of far greater (and more detrimental) consequence, these same biases lead to minimal or non-existent treatment of topics of great importance. One example is that, as of this writing, the Congo Civil War, possibly the largest war since World War II has claimed over 3 million lives, but one would be hard pressed to learn much about it from Wikipedia. In fact, there is more information on a fictional plant