Pivoting off the great point Mike's correspondent made--is it possible that Ted Kennedy (and the rest of the Kennedy clan) actually came through for Obama? If you look at the places Obama made inroads tonight--older voters, white Catholics, Latinos, the white working class--those are all groups with which Kennedy was said to have influence.
I don't know the answer. (If it's a yes, it's a probably a marginal yes. But, as I keep saying, this is a margins game...) But what's less plausible: expecting Ted Kennedy to pay dividends for you among these voters in a single week (roughly the amount of time between the endorsement and Super Tuesday)? Or expecting the effect to unfold gradually over the course of a couple weeks? Several of the demographics I mentioned are generally slow to assimilate news--and they didn't know Obama very well to begin with. It wouldn't shock me if it took them a little while to get up to speed on him, and if the Kennedy endorsement was the beginning of that process.
--Noam Scheiber