I wasn't around during the Bitcoinica fiasco so don't really know the details of how they operated their liquidity. I only know that they were hacked and lost a great deal of Bitcoin.

Just curious as to why liquidity needs to come from Mt.Gox and not from the market?

Isn't it the act of buying/selling from users the source of liquidity?

Mt.Gox isn't a market maker is it?