I have never heard this issue addressed outside of political internet forums and it is always brought up by right-wing, reactionary racists. Which is just as likely to make someone see Obama in a more positive light than a more negative one. I've never heard this question brought up as a means of better understanding Obama as a person and a candidate. It is a ploy to discredit him. In fact, I had a conversation about Obama this weekend with a Republican and the issue was never broached...because unless you have a pre-existing bias against his candidacy,
it is a non-issue. And, for the record, I think I may have secured another vote for Obama.
Vive la Africa!