I think it's a perfectly reasonable assumption that a large portion of the black electorate voted for Obama because of the color of his skin. The increase in black voter turnout/registration definitely suggests a strong correlation.
That being said, why is that important/bad? The vast majority of voters are grossly uninformed about not only the specifics of a given candidate's policy proposals/voting record, but about the mechanics of our government itself. If you want proof, look no further than midterm election voter turnout. Anyone who is even moderately engaged politically, knows that their day to day lives are affected infinitely more directly by their home state senators, reps., and even further localized politicians; and yet the voter turnout in non-presidential elections is under 40%.
People vote for all sorts of arbitrary reasons. I'd venture that a comparable number of people automatically voted
for John McCain because he's not black (relative to the blacks that
voted for Obama)...maybe more. After all, I think blacks only make up
around 13% of the population.
I don't have numbers, but extensive studies have concluded that a candidate's physical attractiveness is every bit as important as any other factor in terms of electability. If you believe that the average person really votes on issues, OR even in their own self-interest, you're kidding yourself. Save the people on the way left and way right, the candidates from the 2 big parties have way more in common, than not. Reason being, it's impossible for a candidate that has "radical" views to get elected here...the American public is incredibly centric. Unfortunately, the media would have you believe that the country is horribly divided with Limbaugh fans on the right and Olberman fans on the left.
The implication that Obama was elected because a bunch of ill-informed voters came out of the woodwork and voted him into office is a fucking joke. Well, in so much that you could make the same exact argument every election. Obama was elected because George Bush's approval ratings were the lowest in history, and the economy had stalled. The lame duck president's party always takes a bath when the economy is in the toilet. Any Democratic nominee was going to win...for better or worse.
If nothing else, we should all be pumped and united on one issue: Politicians are going to have to start paying attention to young people. We showed up and voted in 2008, and if we continue to do so, you're going to see a monumental shift.