So, what caused the Boom?

...was what an old friend of mine asked when I was telling him about the current state of housing and how speculation has driven prices far above what home values really are. But to discover the seed (or fertixlizer) from which speculation blooms is not easy to impart. He was an engineer and me ... a bus. ad major back in the day at Marquette U. I take a lot of economic theory for granted, or rather, I assume that others know it as well.

This morning I found a great article on the very subject titled "How to buy a $450K home for only $750K".