Whether or not that article is correct, that is one snazzy graphic. Let's put some different numbers on it. Adi Shamir and a colleague analyzed the block chain up to block 180,000 and determined that 22% of bitcoins were in circulation (78% have never been transferred between addresses). Assuming that number is still valid, of the 11 million coins that have been mined, about 2.4 million are in circulation. At the current exchange rate, that's $240 million of wealth. Of course, not all of these coins are being exchanged for state backed currency. Many of them are simply transferred between addresses owned by the same person. It's impossible to know how many are exchanged, because even if we knew how much trade was going on at all the exchanges, we know very little about F2F exchanges, like on localbitcoins.com. Also, a lot of the coins are bought and sold multiple times by day traders. If I sell 10 BTC, wait for the price to drop a few percent, and buy back 10.5 BTC, on paper that looks like 20.5 BTC have been exchanged, but really only 0.5 BTC has. So the real question is, how much money will be spent on bitcoins this year by people who don't later sell them. $50 million? Maybe, I have no idea. Now let's look at Silk Road. The $22 million figure for annual sales is a lower bound. Nicolas Christin admits in his paper that he can only estimate the public listings, based on public reviews. We don't know how many stealth vendors and listings there are, and these may be the biggest sales on the site. Vendors build trusted relationships with a few buyers, then go stealth and offer bigger orders. It seems like you would want to, in order to make up for lost public sales. So SR's annual revenue could be twice the lower bound or more. By that measure, SR makes up close to 100% of actual trade for goods and services in the bitcoin economy. Well, who knows. It's all guess work. Don't believe that 20% figure in the article either, because they don't know. But even in this scenario, what would it mean if SR goes out of business? Probably not much. There would still be $200 million in wealth transferred around and day traded, and that would continue, and probably grow.