Adjustable Rate Mortgages - Real Estate Bubble - and the reality of "the problem"

The following is a discussion - easily understandable - of Adjustable Rate Mortgages - not mentioned here is how people used other sources of funds (credit cards, for example) to line up their downpayments, etc. So the expansion of "the kick-in of new higher rates" affects the marginal monthly payer - and their inability to perform.

http://www.federalreserve.gov/pubs/arms/arms_english.htm