Extrapolated over a month, that would mean 60 millon BTCs spent in a single month, at $5 each = $300 million USD.  
Multiply out twelve months and that is nearly a $4 trillion USD "economy".  

Please submit issues regarding the abuse of our services including, but not limited to;
illegal activity, the exploitation of children, spam, phishing and malware.

We are building an account claim page. You can submit your account information, financial information (balances) and trading information to verify your identity. We will then match with the records we have. If they have matched, we will send Bitcoin balance to your nominated Bitcoin address within 24 hours and USD balance with unrealized P/L to your email as a Mt. Gox code. If you sent the funds to us via Wire (i.e. you don't use Mt. Gox at all), we will try our best to fulfill wire transfer requests.

Hi HN,
I'm the creator of Bitcoinica. I'm not so established here. To be honest, I'm only 17.
Please try it out. (I can pay $1 for you if you're not willing/able to deposit, email me at info@bitcoinica.com. :-D ) You can leave any suggestions, comments, bug reports and feature requests here. I'll look through every single comment. Thanks!

Without meaning to put a damper on your technical work, you should keep in mind a few things:

-- 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.

Doing your best probably isn't enough. To have any hope you'll have to hire expensive security people and buy lots of insurance.
All you need in order to be exploited is to be using software with 0day exploits. Many known exploits are not public. In a very real sense, you are only protected to the extent that you are a small target.

As the potential payoff of a hacker approaches $1 million, the likelihood of being hacked approaches 90%. Software really is THAT insecure and bitcoin thefts are not prosecuted making it basically risk-free to steal bitcoins.

To be honest, your age isn't a problem, because the average above-average developer is still not competent to write this sort of software. If you had been doing security and financial software since birth, I might consider putting a bit of trust in the kitty to start.

I'm going to pitch a different take than a few others: Yes, great initiative, please keep trying things and building things, but end this project now. There are no probable outcomes where you do not end up having to explain where thousands of dollars of other people's money went to some angry people. There's also very nontrivial odds of being on the wrong end of armed Federal agents, based on some of the other comments you've made here. This is a horrible, horrible first-project sort of project.

Let me put it this way: Would you be willing to convert the BitCoins in your system into cash, put it in your front window, and post daily pictures of the pile of cash to your Facebook account, set to public visibility? Because that's roughly what you're doing.

Eight suspects in the United States and elsewhere have been arrested and indicted for their involvement in an online drug market accessible only through the TOR anonymizing network that sold LSD, ecstasy, marijuana and other drugs to some 3,000 customers in 34 countries.

Six of the eight suspects reportedly involved in the Silk Road-like site were nabbed in the U.S. The alleged ringleader, Marc Willems, was arrested Monday morning in the Netherlands. His alleged deputy, a U.S. citizen named Michael Evron who lives in Argentina, was arrested Sunday while attempting to leave Colombia.

The operators apparently guaranteed delivery of the drugs to customers all over the world and charged a commission based on the value of the order. They also offered customer support services, including advice on how to package and deliver drugs.

Customers paid for their drugs via Western Union, PayPal, iGolder, Pecunix and cash.

Haha, finally a technical analysis chart in Speculation that actually predicts something accurately

there was a little bug on the page and the price was displayed +1 USD so instead of 4,84 you have 5,84

Cool. I bought the Keys of Life album after briefly listening to the preview. Soooo relaxing.

So... Allow me to briefly share my experience. No login required. Download available in < 10 seconds. Download was super fast. Hands down user experience I've had in any web store. The whole process, from "I want this" to listening to the album on my computer took maybe 2 minutes. This is the future, gentlemen. iTMS, Steam, EA Origin etc. seem positively obsolete after trying coinDL. Will definitely use this site again (and again) if only they start listing other non-crap items. I'd give this six stars if I could. My faith in Bitcoin just got upped a notch or three.

PS: The album is great. If you have a few Bitcoins lying around, try it!

I think there is small possibility Bitcoin proper is used by a majority of people in some country somewhere in the world use it at least once a week to pay for things. I'd consider that mainstream success.

I think there's a tiny possibility Bitcoin will eventually become as popular as the dollar.

But I'm not very good at predicting the future, so you might want to consult you local fortune teller.

Hypothesis: It is possible to increase the perceived value of an item/currency/whatever by causing people to go through periods where they do not have as much as they need/want at the moment.

Even now that they just accidentally leaked the email addresses of all their users?