I could almost hear the collective groans of disbelief as soon as readers read my forecast. It was a column I wrote almost three years ago, warning about the impending U.S. real estate crisis and projecting that home prices were set to tumble by as much as 40%. Turns out I actually under-estimated the scale of the bust. Prices have fallen much more than that in some areas - and may fall even further. The are obvious reasons for this. The economic recession. The evaporation of available credit.