Is this a new story? I'm not convinced that it is. Because the writing is not very clear, it is possible that something new happened last fall because Barack Obama was on the ballot, but I'm not so sure. There have been previous studies of the electorate that have produced similar findings. For example, this depiction of the demographics of the 1996 California electorate suggests that Blacks voted in greater numbers than their raw proportion of the state's population in that year. (So did whites, by a lot, that year; evidently Asian-Americans and Latinos were not voting or not eligible because of age or immigration status.)
The real story here is that, when they can, Black people vote.
Maybe last year this happened because Blacks identify with Barack Obama, but the phenomenon long precedes his rise. Maybe Blacks are raised to remember that their grandparents fought for the right to cast a ballot. Maybe Blacks cling to a belief that has become uncommon among white citizens, a belief that the doings of government is essential to our collective well-being.
The conclusion remains simple: when they able to, Black people vote.