To me, it is not all that significant that 44% of Michigan Democrats did not vote for Hillary Clinton. For one thing, Fox News polled Democrats and found that, had all the names been on the ballot, she would still have won by a double-digit margin. For another, there were plenty of paid efforts to gin up the uncommitted vote. And nowhere in the country does Clinton currently command a majority. So Michigan's results are unremarkable. There is some good news for Obama: 73% of the uncommitted Dems say they'd have preferred him.
The one trouble spot for Clinton is obvious: 70% of black voters sampled chose "uncommitted." The sample size was small -- I'm guessing about 300 or so of the exit poll sample were black -- but it's a sign that Obama has consolidated the black vote in Michigan and probably elsewhere.
Do not be surprised to see the Clinton campaign begin to rachet down expectations in South Carolina on the theory that if people expect Obama to win here, his win won't be seen as all that and a bag of chips.