Correct all those securities are sitting on the FED balance sheet receiving coupon flows (interest payments).
These interest payments can then be used to: 1) go onto the secondary market and purchase more securities (without the need to expand the money supply so its not strictly QE) 2) be remitted straight to the US treasury as revenue
Whilst this means there will now be ongoing market operations keeping interest levels low, it won't be of the same magnitude as the QE's.
Personally I think QE 3 or QE 2 extension will occurr as there is simply not enough tax revenue and too much spend in US.
