EDIT: panarky has now updated his post above to make it clear that the advice was to Zhou Tong.
I don't wish to link the Bitcoinica fiasco with my leave because I sold Bitcoinica a few months ago. And I lost my control in January. Basically everything didn't go as I planned. (I'm VERY conservative about wallet security.)
I wanted to build an independent exchange system to replace hedging, so that most funds can stay offline. But the new owner didn't like the idea.
I know it failed like predicted, but my involvement in the failure is highly limited. I sold the site for the same reasons: What if someday I'm hacked, or caught? (The valuation (P/E) was less than 1!)
I'm a web developer, not a security expert. I know how to protect the API keys but I'm not good at encrypting a wallet.dat. That's all I thought since day one.
I thought jellicle's advice to Zhou Tong was insightful 248 days ago. Time has proven its wisdom.
http://news.ycombinator.com/item?id=2973803
-- systems that work with money are attacked hard and often, by intelligent skilled people
-- in fact some of the people who attack your system are likely to be both more skilled and more intelligent than you are
-- systems that work with money that fail, fail spectacularly ("What do you mean someone withdrew $8 million last night?")
-- banking websites, Paypal, etc. are all like icebergs - you don't see 9/10ths of the things they've done to prevent spectacular failure
-- spectacular failure is your destiny if you don't work very hard to prevent it
-- spectacular failure may be your destiny even if you do work very hard to prevent it
You should plan accordingly.