An interesting post . . . but may I make a couple of suggestions?
When you make a statement like I "was worried about the tales people chat of no black civilizations or nations prior to european contact. and i wanted to correct that", you might want to offer an example of those conversations. Are people on DU saying that? I'm not saying they aren't, but I haven't seen anything like it and would be interested in what you have found.
You might also want to consider formatting your posts a bit - while I am aware that many people believe that capitalization is passe, it does help with reading clarity, as does breaking a post into smaller 'chunks'. I won't say paragraphs, but adding a blank line every few sentences really does make it easier to read a longer post.
If it is easier to read, it is more likely that people will actually read it, right?
If you are interested, there are a few more scholarly resources than Wikipedia (reader edited sources are suspect). The Google books are not complete (they leave out sections) but still interesting and you could always check out copies from the library if interested in reading them completely:
http://www-sul.stanford.edu/depts/ssrg/africa/history/hisking.html (a link of links - very useful)
http://books.google.com/books?id=TV-0AaV_4EsC&lpg=PR9&ots=zlyajfH9vY&dq=early%20african%20civilizations&lr&pg=PA3#v=onepage&q=early%20african%20civilizations&f=falsehttp://books.google.com/books?id=ga7QqZw6VPYC&lpg=PR9&ots=rXspZYfbIJ&lr&pg=PR9#v=onepage&q&f=falsehttp://books.google.com/books?id=Ap2rW2pddEcC&lpg=PA23&ots=R1JtFRPNAe&dq=early%20african%20civilizations&lr&pg=PA23#v=onepage&q=early%20african%20civilizations&f=falsehttp://www.wsu.edu/~dee/CIVAFRCA/IRONAGE.HTM (also check some of the links at the bottom of the page - some work, some don't)