The Down and Dirty today - Exit polls - WSJ

From the WSJ:

1. Exit polls in 2008 indicated that 74% of those who cast ballots were white. If the white share of the electorate drops, say to 72%, it seems pretty clear Mr. Obama will win. If it rises, to say 76%, that means Mr. Romney likely is going to win. If the level stays constant, it could be a long night. Parallel question: Can Mr. Obama win 40% or more of the white vote? If he does, he’ll be in good shape.
2. The performance of young adults is either Mr. Obama’s secret weapon or his Achilles’ heel. In pre-election polling, two findings stand out: Mr. Obama still is favored by a wide margin among voters aged 18 to 29, but the interest they express in this election is below that of four years ago. So, the question is whether they come out to vote even if they aren’t as enthused as before
3. Mr. Romney may well need to win Virginia’s 13 votes first for Ohio to matter later. Let’s assume, for example, that Mr. Romney wins North Carolina, Florida and Ohio as well as the swing states of New Hampshire and Colorado. He would still come up four electoral-college votes short of the 270 needed to win without Virginia.
4. To get a better sense of what’s happening in Ohio, don’t just watch the state vote totals. Watch a few key counties. Wall Street Journal counties expert Dante Chinni points to three. One is Hamilton, the home of Cincinnati and a county the Journal has been watching all year. Mr. Obama captured it in 2008, the first time a Democrat had done so since 1964. He doesn’t have to win it this time, but he has to make it close. Also watch Wood and Ottawa, two counties between Toledo and Cleveland that have gone with the state’s winner in every presidential election since 1992.