20110823 比特幣，一種虛擬的交換媒介

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Cryptocurrency
The bitcoin, a virtual medium of exchange, could be a real alternative to government-issued money—but only if it survives hoarding by speculators.
By James Surowieckiarchive page
August 23, 2011

When the virtual currency bitcoin was released, in January 2009, it appeared to be an interesting way for people to trade among themselves in a secure, low-cost, and private fashion. The Bitcoin network, designed by an unknown programmer with the handle “Satoshi ­Nakamoto,” used a decentralized peer-to-peer system to verify transactions, which meant that people could exchange goods and services electronically, and anonymously, without having to rely on third parties like banks. Its medium of exchange, the bitcoin, was an invented currency that people could earn—or, in Bitcoin’s jargon, “mine”—by lending their computers’ resources to service the needs of the Bitcoin network. Once in existence, bitcoins could also be bought and sold for dollars or other currencies on online exchanges. The network seemed like a potentially useful supplement to existing monetary systems: it let people avoid the fees banks charge and take part in noncash transactions anonymously while still guaranteeing that transactions would be secure.

Yet over the past year and a half Bitcoin has become, for some, much more. Instead of a supplement to the dollar economy, it’s been trumpeted as a competitor, and promoters have conjured visions of markets where bitcoins are a dominant medium of exchange. The hyperbole is out of proportion with the more mundane reality. Tens of thousands of bitcoins are traded each day (some for goods and services, others in exchange for other currencies), and several hundred businesses, mostly in the digital world, now take bitcoins as payment. That’s good for a new monetary system, but it’s not disruptive growth. Still, the excitement is perhaps predictable. Setting aside Bitcoin’s cool factor—it might just as well have leapt off the pages of Neal ­Stephenson’s cult science-fiction novel Snow Crash—a peer-to-peer electronic currency uncontrolled by central bankers or politicians is a perfect object for the anxieties and enthusiasms of those frightened by the threats of inflation and currency debasement, concerned about state power and the surveillance state, and fascinated with the possibilities created by distributed, decentralized systems.

Bitcoin is not going to make government-backed currencies obsolete. But while the system’s virtues, such as anonymity and the lack of bank fees, may not matter much to most consumers, one can envision it being useful in a variety of niche markets (some legal, others not, like recreational drugs). Where anonymity is valuable, where trusted third parties are hard to find or charge high rates, and where persistently high inflation is a problem, it’s possible that bitcoins could in fact flourish as an alternative currency.

Before they become such an alternative, though, the system will have to overcome a major, and surprising, problem: people have come to see it primarily as a way to make money. In other words, instead of being used as a currency, bitcoins are today mostly seen as (and traded as) an investment. There’s a good reason for that: as people learned about Bitcoin, the value of bitcoins, in dollar terms, skyrocketed. In July 2010, after the website Slashdot ran an item that introduced the currency to the public (or at least the public enthusiastic about new technologies), the value of bitcoins jumped tenfold in five days. Over the next eight months, the value rose tenfold again. This attracted an enormous amount of publicity. More important, it also made people think that buying and holding bitcoins was an easy way to make a buck. As a result, many—probably most—Bitcoin users are acquiring bitcoins not in order to buy goods and services but to speculate. That’s a bad investment decision, and it also hurts Bitcoin’s prospects.


Things Reviewed
Bitcoin
www.bitcoin.org
True believers in Bitcoin’s usefulness prefer to deny that speculation is driving the action in bitcoins. But the evidence suggests otherwise. The value of the currency has been tremendously volatile over the past year. A bitcoin has been worth as little as a few pennies and as much as $33, and after seeming to stabilize at around $14 over the summer, the bitcoin’s value tumbled by almost 50 percent in a matter of days in August. Media coverage has had an outsized impact on the value of bitcoins, even when it has not had a major impact on the number of transactions conducted. Blog posts in which people talk about buying bitcoins because of how much they’ve increased in value are common. In May, Rick Falkvinge, founder of the Swedish Pirate Party, which focuses on patent and copyright reform, posted that he had decided to put all his savings into Bitcoin. Although he had previously published a series of posts arguing for the bitcoin’s viability as a currency, his first listed reason for investing in bitcoins was that their value had risen a thousandfold against the U.S. dollar in the previous 14 months. That’s classic speculative thinking.

The problem with having the Bitcoin economy dominated by speculators is that it gives people an incentive to hoard their bitcoins rather than spend them, which is the opposite of what you need people to do in order to make a currency successful. Successful currencies are used to transact day-to-day business and lubricate commerce. But if you buy bitcoins hoping that their value will skyrocket (as anyone investing in bitcoins would), you’re not going to be interested in exchanging those bitcoins for goods, since then you’ll lose out when the value of bitcoins rises. Instead, you’re going to hold onto them and wait until you can cash out.

This kind of hoarding is made more likely by the way Bitcoin is set up. Whereas the supply of modern, “fiat” currencies is controlled by central banks, the supply of bitcoins is permanently limited; there will never be more than 21 million bitcoins in existence. (The total number of coins is a result of the system’s initial rules governing how many bitcoins miners could earn, and how often.) Bitcoin’s limited money supply is one of the things that people like about it: the currency cannot be debased, as money can when central bankers print more of it. But the flip side is that if the demand for bitcoins rises, for whatever reason, then the value of bitcoins will necessarily rise as well. So if you think that bitcoins are going to become more and more popular, then—again—it’s foolish to spend your bitcoins today. The rational thing to do is hoard them and eventually sell them to new users. But that means there will be fewer bitcoins in circulation (and more in people’s virtual wallets), making them less useful as an actual medium of exchange and making it less likely that businesses and consumers will ever see Bitcoin as legitimate.

Now, even traditional currencies can be subject to this kind of cycle, which economists call a “deflationary spiral”—although with conventional currencies, the cycle occurs when falling prices lead people to start hoarding cash in the expectation that prices will keep falling (which in turn holds down demand and makes prices fall further). The quintessential recent case is Japan after its real-estate bubble burst in the 1990s.

With ordinary currencies, though, there’s a limit to how far down the spiral can go, since people still need to eat, pay their bills, and so on, and to do so they need to use their currency. But these things aren’t true of bitcoins: you can get along perfectly well without ever spending them, so there’s no imperative for people to stop hoarding and start spending. It’s easy to imagine a scenario in which the vast majority of bitcoins are held by people hoping to sell them to other people.

We may already be living in that scenario, since despite all the buzz about Bitcoin, the number of actual transactions conducted in bitcoins, and the value of those transactions, has been shrinking. According to bitcoinwatch.com, the best source of Bitcoin data, more than a million dollars’ worth of bitcoins were traded on June 13. By early August, less than half a million dollars in bitcoins were being used in transactions; even the currency’s value had been cut in half. Successful network technologies do not tend to see usage plateau, let alone shrink, this early in their history. And the lack of growth in the number of transactions conducted via Bitcoin is not what you’d expect to see if the technology were, as Falkvinge said, on its way to being a part of “normal daily commerce.” It’s true that there aren’t all that many goods and services one can (or would want to) buy with bitcoins. But in a way, that’s the real problem: a falling rate of use makes businesses less, not more, interested in accepting bitcoins, and ordinary consumers less interested in spending them.

So just now the bitcoin boom of the past year looks not so much like the birth of a new currency as like a classic bubble. And this has created a real paradox for bitcoin enthusiasts. The best thing for bitcoins would be for people to stop thinking of them as an investment and start thinking of them as a currency. That probably requires the bubble to burst, as it may be doing right now. But if the bubble bursts, it’s possible that people’s interest in Bitcoin will just fade away. After all, would you accept bitcoins in exchange for your work or products if you knew their value had fallen 50 percent in a matter of days? The challenge for Bitcoin now is whether, having become popular because of the cycle of hype, it can somehow avoid being devoured by it. Only then might we be able to say, Good-bye, asset; hello, currency.

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by James Surowiecki

加密貨幣
比特幣，一種虛擬的交換媒介，可能成為政府發行貨幣的真正替代品--但前提是它必須撐過投機者的囤積。
作者
James Surowieckiarchive page
2011年8月23日
2009 年 1 月，當虛擬貨幣比特幣發佈時，它似乎是人們之間進行安全、低成本和私密交易的一種有趣方式。比特幣網絡是由一位不知名的程式設計師「中本聰」所設計，使用分散式點對點系統來驗證交易，這意味著人們可以匿名地以電子方式交換商品和服務，而不必仰賴銀行等第三方。它的交換媒介比特幣是一種發明的貨幣，人們可以通過借出自己的電腦資源來滿足比特幣網絡的需求，從而賺取比特幣，用比特幣的行話來說就是 「挖礦」。一旦存在，比特幣也可以在線上交易所買賣，換取美元或其他貨幣。比特币网络似乎是对现有货币体系的一个潜在的有益补充：它可以让人们避免银行收取的费用，匿名参与非现金交易，同时还能保证交易安全。
然而，在過去的一年半中，對某些人來說，比特幣已經變得更多。它不再是美元經濟的補充品，而是被吹捧為競爭對手，推銷者幻想著比特幣成為主導交易媒介的市場。誇張的詞彙與平凡的現實不成比例。每天都有數以萬計的比特幣進行交易（有些用於購買商品和服務，有些用於交換其他貨幣），而且有幾百個企業（大多數是數位世界的企業）現在接受比特幣作為付款方式。這對於一個新的貨幣系統來說是好事，但並不是顛覆性的成長。不過，這種興奮也許是可以預見的。撇開比特幣的酷炫因素不談--它就像從 Neal Stephenson 的邪典科幻小說《雪崩》（Snow Crash）中蹦出來的一樣--一種不受中央銀行家或政客控制的點對點電子貨幣，是那些被通貨膨脹和貨幣貶值威脅嚇怕、擔心國家權力和監視國家，以及對分散式、去中心化系統所創造的可能性著迷的人們的焦慮和熱情的完美對象。
比特幣不會使政府支持的貨幣過時。但是，儘管該系統的優點，如匿名性和無銀行費用，對大多數消費者來說可能並不重要，但可以預見它在各種利基市場（有些合法，有些不合法，如娛樂性藥物）是有用的。在匿名性有價值的地方，在可信賴的第三方難以找到或收費高昂的地方，在通貨膨脹持續高企的地方，比特幣有可能作為一種替代貨幣而蓬勃發展。
不過，在比特幣成為替代貨幣之前，這個系統必須克服一個重大且令人驚訝的問題：人們已經將比特幣視為一種主要的賺錢方式。換句話說，比特幣現在大多數不是被當作貨幣使用，而是被當作一種投資（和交易）。這有一個很好的原因：隨著人們對比特幣的了解，比特幣的價值，以美元計算，暴漲。2010 年 7 月，在 Slashdot 網站上刊登了一篇向大眾（至少是熱衷於新科技的大眾）介紹比特幣的文章之後，比特幣的價值在五天之內暴漲了十倍。在接下來的八個月中，價值又再漲了十倍。這吸引了大量的宣傳。更重要的是，這也讓人們認為購買和持有比特幣是賺錢的簡單方法。因此，很多--可能是大多數--比特幣用戶獲取比特幣並不是為了購買商品和服務，而是為了投機。這是一個糟糕的投資決定，也傷害了比特幣的前景。
事件回顧
比特幣
www.bitcoin.org
真正相信比特幣有用的人寧願否認投機正在推動比特幣的行動。但證據顯示並非如此。在過去的一年裡，比特幣的價值一直在大幅波動。一個比特幣的價值從幾分錢到 33 美元不等，在夏天似乎穩定在 14 美元左右後，比特幣的價值在八月的幾天內暴跌了近 50%。媒體報導對比特幣價值的影響過大，即使在媒體報導並未對交易數量造成重大影響的情況下。博客文章中，人們談論購買比特幣，因為比特幣的價值增加了很多，這是很常見的。今年五月，專注於專利和版權改革的瑞典海盜黨創始人 Rick Falkvinge 發帖說，他決定把所有積蓄都投入比特幣。雖然他之前發表了一系列文章，論證比特幣作為貨幣的可行性，但他列出的第一個投資比特幣的理由是，在過去的 14 個月中，比特幣兌美元的價值已經漲了一千倍。這是典型的投機思想。
投機者主導比特幣經濟的問題是，這會鼓勵人們囤積比特幣，而不是花掉它們，這與你需要人們做什麼才能讓一個貨幣成功的想法剛好相反。成功的貨幣是用來交易日常業務和潤滑商業的。但如果你買比特幣是希望它的價值會暴漲（就像任何投資比特幣的人一樣），你就不會有興趣用這些比特幣來交換商品，因為這樣你就會在比特幣價值上升時蒙受損失。相反的，你會持有它們，等到你可以兌現的時候。
比特币的设置方式使得这种囤积行为更有可能发生。現代 「法定 」貨幣的供應是由中央銀行控制的，而比特幣的供應是永久有限的；現存的比特幣永遠不會超過 2100 萬個。(比特幣的總數是由於系統的初始規則，規定了礦工可以賺取多少比特幣，以及賺取的頻率)。比特幣的有限貨幣供應是人們喜歡它的原因之一：這種貨幣不能被貶值，就像中央銀行家印刷更多的貨幣一樣。但反過來說，如果對比特幣的需求上升，不管是什麼原因，那麼比特幣的價值也必然會上升。So if you think that bitcoins are going to become more and more popular, then—again—it’s foolish to spend your bitcoins today. 理性的做法是囤積它們，最後再賣給新的使用者。但這意味著流通中的比特幣會越來越少（而在人們的虛擬錢包中的比特幣卻越來越多），這使得比特幣作為實際交易媒介的作用越來越小，也使得企業和消費者更不可能將比特幣視為合法貨幣。
現在，即使是傳統貨幣也會受到這種循環的影響，經濟學家稱之為 「通縮螺旋」--雖然對於傳統貨幣來說，這種循環發生在價格下跌導致人們開始囤積現金，以預期價格會繼續下跌的時候（這反過來又抑制了需求，使得價格進一步下跌）。最近最典型的案例就是日本在 1990 年代房地產泡沫破滅之後。
不過，對於一般貨幣而言，螺旋式下跌的程度是有限的，因為人們還是需要吃飯、付帳單等等，而且他們需要使用貨幣。但比特幣並不是這樣：你可以完全不花比特幣，所以人們沒有必要停止囤積比特幣並開始消費。我們很容易就可以想像，絕大多數的比特幣都是由希望將它們賣給其他人的人所持有。
我們可能已經生活在這樣的情景中了，因為儘管有關比特幣的討論很熱烈，但比特幣的實際交易數量以及這些交易的價值一直在萎縮。根據比特幣資料的最佳來源 bitcoinwatch.com，6 月 13 日的比特幣交易價值超過一百萬美元。到了八月初，只有不到五十萬美元的比特幣被用於交易；甚至比特幣的價值也減少了一半。成功的網路技術往往不會在其歷史的早期就出現使用量趨於平穩的現象，更不用說萎縮了。而且通過比特幣進行的交易數量沒有增長，這並不是你所期望看到的，如果該技術正如 Falkvinge 所說，正在成為 「正常日常商業 」的一部分。人們可以（或想要）用比特幣購買的商品和服務確實不多。但在某種程度上，這才是真正的問題：使用率的下降使得企業對接受比特幣的興趣減少，而不是增加，而普通消費者對使用比特幣的興趣減少。
因此，過去一年的比特幣熱潮，看起來不像是新貨幣的誕生，倒像是典型的泡沫。這對比特幣熱衷者來說是一個真正的悖論。對比特幣來說，最好的結果是人們不再把它當作一種投資，而是把它當作一種貨幣。這可能需要泡沫破滅，就像現在一樣。但如果泡沫破滅了，人們對比特幣的興趣有可能就會消失。畢竟，如果你知道比特幣的價值在幾天內下跌了 50%，你還會接受比特幣來交換你的工作或產品嗎？比特幣現在面臨的挑戰是，在因為炒作循環而變得流行之後，它是否能以某種方式避免被炒作所吞噬。只有這樣，我們才有可能說，再見，資產；你好，貨幣。
作者： James Surowiecki