[Toddsterpatriot]

but putting this in my terms sounds like using a credit card to pay off a credit card

More like investing bond interest (mortgages) into new bonds (Treasuries).

[CutePuppy]

... but putting this in my terms sounds like using a credit card to pay off a credit card

Credit card is run by the Congress and Obama administration, not by the Fed. Quantitative easing doesn't add a dollar to national debt. In fact, QE1 provided the excess capital at the Fed that they can use now to add some liquidity and remove some uncertainty (capital reserves against loan portfolios) from the financial market. Monetary policy by the Fed is never a panacea against the destructive Keynesian "spend it and forget it" fiscal policy.

More like investing bond interest (mortgages) into new bonds (Treasuries).

Exactly. Fed has a surplus due to TARP principal and interest repayments and the higher interest on MBS portfolio from QE1 that Fed ended in March of 2010. The case for QE2 (whether one agrees or disagrees) is pretty well stated in this FR thread - Ben at the controls [Bernanke, the Fed] - FR / NYP, 2010 August 10