After 9/11, pundits quickly adopted the mantra "this changes everything." At the time, the statement rang false to me. And five years later, it's clear that trends underway before the attacks -- such as a shift from intellectual to land-based sources of growth, tax and interest rate cuts, and global intergration -- continued -- and in some cases were accelerated -- by policy decisions that followed 9/11. At least one trend resulting from these decisions -- the rise in housing prices -- is likely to reverse in the next five years -- with important implications for investors.

A few hours after the attacks, I was on the phone to Amey Stone, then of BusinessWeek Online, discussing their possible effects on the economy and markets. I felt a mixture of sorrow, fear and defiance as we discussed these relatively trivial topics on that historic day. On September 12, Waiting for the Wall Street Crunch appeared -- suggesting that the attacks would accelerate trends already underway -- such as tumbling stock prices and the Fed's January 2001 decision to lower interest rates to cushion the economic fallout from 2000's tech stock meltdown. The article also speculated about another attack and what that might mean for the economy and stocks.

Specifically, 9/11 followed four economic trends which were underway at the time of the attacks: