Yesterday I posted data from Yahoo! Buzz that showed Mitt Romney topping searches among Republican voters in Nevada and much closer numbers among Romney, John McCain, and Mike Huckabee in South Carolina. Now some data about Democratic voters in Nevada and South Carolina suggests a dead heat between Clinton and Obama.

As the chart below shows, Hillary Clinton and Barack Obama have been locked in a tight battle for attention from online voters in Nevada. They both began climbing in web searches this week, probably because of increased focus on the caucus, and are now almost tied. John Edwards is far behind the frontrunners, and poor Dennis Kucinich is flatlining around zero.

In South Carolina things are much the same, though there are fewer voters searching for the candidates. That should change as we approach the Jan. 26 primary.

As I've been careful to mention before, neither we nor Yahoo! are claiming that these numbers are accurate predictions; they're simply an indicator of interest in the candidates in early states. That said, the data has correlated pretty closely to the outcome of the Iowa caucus and the primaries in New Hampshire and Michigan.

What we're most likely looking at here is the searching habits of undecided voters. The Nevada caucus is tomorrow, and if the above chart is any indication it's a toss-up between Clinton and Obama.