We present a simple order book mechanism that regulates an artificial
financial market with self-organized criticality dynamics and fat tails of
returns distribution. The model shows the role played by individual imitation
in determining trading decisions, while fruitfully replicates typical aggregate
market behavior as the "self-fulfilling prophecy". We also address the role of
random traders as a possible decentralized solution to dampen market
fluctuations.Comment: 18 pages, 10 figure