I know our commenters are fed up with our collective Sharpton preoccupation, but I was just thinking about that Sharpton endorsement when I saw Mike's item. I guess I disagree with him a bit. While Hillary would love Reverend Al's seal of approval, I don't think Obama feels the same way. For him, the best-case scenario would be if Sharpton stayed out altgother. (Highly unlikely, I know. But one can dream. Call it the "audacity of hope.")
You probably see the logic yourself. If not, here's why: If Sharpton endorses Hillary, it gives her somewhat more cred in the black community. But Obama now has close to all the credibility he needs in the black community. Sharpton does next to nothing for him there (except maybe in some pockets of Brooklyn and Manhattan, but I suspect New York's a lock for Hillary either way). The only thing Sharpton does for Obama is alienate white voters, who see Sharpton as a racially polarizing figure.
Having said that, Obama can't exactly spurn Sharpton, since he can stir up small-scale "not black enough" problems for the senator. So it's a bit of a conundrum that Obama would obviously prefer to avoid.