Back in the dot-com era, iTulip.com found parallels between the Netherlands 1600s tulip craze and the late-90s/pre-9/11 internet bubble. They’ve relaunched to comment on the housing bubble:
In the past the Fed has been very quick to stop speculation in real estate, much more quickly than stock market speculation. Why? Real estate involves the banking system much more than does the stock market and looking after the banking system is Job One for the Fed. Letting millions of homeowners buy real estate they can’t afford with mortgages they can never pay back is a surefire road to mass defaults that can cripple the banking system.