I thought this was pretty interesting:
http://www.pollster.com/mystery_pollster/ever_since_polls_from_abc.phpfavorable / unfavorable rating of Hillary Clinton:
white Democrats: 56% fav. / 15% unfav.
black Democrats: 66% fav. / 4% unfav.
favorable / unfavorable rating of Barck Obama:
white Democrats: 41% fav. / 4% unfav.
black Democrats: 43% fav. / 1% unfav.
(Remaining %age for each were either "undecided" or "haven't heard enough" about the candidates.)
So both white and black Democrats who know enough about Obama to form an opinion overwhelmingly like him. Nearly the same is true of Clinton, except that there's a minority of white Democrats who don't like her. My guess is that that demographic heavily overlaps with the "netroots" types, which seems to be a demo that's skewed towards whites, and which includes a lot of people who are very upset with Clinton about her support for the war.
