Once again for posterity:
https://bitcointalk.org/index.php?topic=400235.msg8663871#msg8663871Remember if you only have $100 in your economy, but it changes hands 1 million times per year, that is a $100 million nominal GDP.
Velocity is value. Excessive stored money is correlated with a Dark Age (we are still digging up bullion hordes from the Middle Ages).