In this case, "stacking" is actually an old idea. Back when
paper was
scarce, and
books were
highly at
risk, monks would
memorize literally whole
volumes of information by building a
memory palace. Said
palace was a whole interconnected series of
mental rooms that had
objects and
decorations, with each item being
associated with a particular piece if information.
Whole
speeches can easily be memorized this way.
For more information on this subject, try Thomas Harris' Hannibal, or
http://www.jeanhouston.org/programs/lectures/memory/14ms7Centuries-51.html