Mean absolute error (MAE) during the out-of-sample period is 0.486 for GFT, 0.311 for lagged CDC, and 0.232 for combined GFT and CDC.
A combination of GFT search behavior and actual CDC numbers produced the best model for the authors of this paper. The (media) spin is "GFT as a stand-alone flu tracker fails".
Perhaps the article would be of a different tone if the researchers had full access to Google's data. I don't think the mentions of irony, failure, misleading and hubris are deserved nor offer a fair portrayal.