This seems like a great trending topic detection algorithm, but nothing revolutionary. The "hours in advance" part is probably more to do with the scale of twitter's data and their decisions about when to publish topics on their website than it does the novelty of the approach.

It seems like a great and tested method for developing your own trending topics algorithm, which could be useful in other contexts. I wonder if this could be applied to corporate email servers to let management spot issues before they're brought up.