????每隔幾年，技術(shù)世界就會爆發(fā)一場革命，迎來下一個有望改變?nèi)祟惿罘绞健⒋呱粋€高利潤新產(chǎn)業(yè)的大事物。繼個人電腦爆炸式發(fā)展之后，互聯(lián)網(wǎng)、智能手機(jī)、平板電腦、云計算，以及其他大大小小的顛覆性技術(shù)接踵而至。最新一個粉墨登場的變革者似乎是虛擬貨幣，而在這一領(lǐng)域，最大的玩家當(dāng)然非比特幣莫屬。

????從表面上看，比特幣似乎是一個偉大的創(chuàng)意，或許也是一種必然產(chǎn)物。比特幣（這個虛擬貨幣的實際單位）是一種可以由買賣雙方直接交易的電子貨幣，它不需要黃金、美元或其他傳統(tǒng)的價值儲存手段提供實體支持，價格完全基于一個點對點式網(wǎng)絡(luò)自發(fā)形成的需求。比特幣與主流貨幣的差異并不大——自國際貨幣體系于20世紀(jì)70年代廢除金本位制、創(chuàng)建浮動匯率以來，就連美元基本上也遵循著同樣的運(yùn)作原則。

????最大的區(qū)別在于監(jiān)管。不同于現(xiàn)金，比特幣不受中央銀行支持，而傳統(tǒng)貨幣的實際價值其實是由中央銀行確定的。

????為了理解這一點，試想一位店主按照一個固定價格向顧客出售方糖塊的情形。走進(jìn)店鋪前，這位顧客知道他兜里的美元將產(chǎn)生一定量的價值。盡管這種價值（即美元的價格）在外匯市場上或許會波動，但只會在一個狹窄的區(qū)間內(nèi)變化，不會影響這位顧客實時購買方糖塊的能力。如果美元價值的波動遠(yuǎn)遠(yuǎn)超出一個可接受的范圍，央行通常會采用貨幣交易的方式對它進(jìn)行矯正，讓它回到正常的區(qū)間內(nèi)。這正是一種不與黃金掛鉤的法定貨幣依然可以有效運(yùn)轉(zhuǎn)、不會因貨幣投機(jī)者作祟而遭到破壞的原因所在。

????相比之下，比特幣的波動性使得這一切毫無確定性可言。店主和顧客都不知道如何在任何特定時間內(nèi)給方糖塊正確定價，因為這種虛擬貨幣的價值往往呈現(xiàn)大起大落之勢。過去一年，一個比特幣的價格曾經(jīng)從14美元暴漲至1,100美元，2013年年末又回落到了500美元左右。如此大幅度的波動不僅使得交易雙方根本無法預(yù)測比特幣的價值，而且也讓它變得幾乎一錢不值。劇烈波動的原因是，由于缺乏任何官方的貨幣之錨，比特幣只存在于物物交換或投機(jī)的背景之下，但當(dāng)交易和炒作終止時，一切圍繞比特幣的喧囂也將偃旗息鼓。換句話說，比特幣的成功完全基于一個自我實現(xiàn)的預(yù)言，這種狀況就像聽起來那樣危險，比特幣甚至無法通過一種真實貨幣理應(yīng)經(jīng)受的考驗。

????此外，比特幣的不可替代性也是一個小問題。舉一個很有說服力的例子：有個人因扔掉了一個硬盤驅(qū)動器而損失了價值約750萬美元的比特幣。當(dāng)然，我們也可能一時記不起把現(xiàn)金放在什么地方，但幾乎不會如此輕易地丟失如此巨額的現(xiàn)鈔。這項因素，再加上上文提及的種種問題，使得比特幣成為一種極其不可靠的交易媒介，進(jìn)而貶損其價值主張，也就是它的匿名性、交易免稅、比信用卡更低的交易成本等。

????最后不得不提一下絲綢之路(Silk Road)，這家以比特幣作為交易媒介的在線黑市最近被美國監(jiān)管當(dāng)局關(guān)閉。由于匿名性和點對點體系，比特幣備受非法貨物交易者的青睞。對于比特幣的投資者來說，這或許是個好兆頭，但這種使用方式幾乎肯定會受到執(zhí)法者的注意，遲早會被取締（絲綢之路就是一個例子），而且有可能導(dǎo)致監(jiān)管部門對它的使用方式施加重重限制。本周舉行的達(dá)沃斯世界經(jīng)濟(jì)論壇(World Economic Forum)上，美國金融界大佬對比特幣的前景表達(dá)了類似的看法。“問題不在于我們是否接受，”摩根大通(JPMorgan)首席執(zhí)行官吉米?戴蒙接受美國全國廣播公司財經(jīng)頻道(CNBC)采訪時說。“我們現(xiàn)在連能否為比特幣交易提供方便都成問題。說到底，對比特幣不放心的人是政府。”

????Every few years the world of technology witnesses a revolution, the next big development with the potential to change how we function and to spawn a highly profitable new industry. There's been the explosion of personal computers, followed by the Internet, smartphones, tablets, cloud computing, and other large and small disruptive technologies. The latest such game-changer seems to be the arrival of virtual currencies, personified by the biggest player in that arena: bitcoin.

????On the surface, bitcoin seems like a great idea and maybe an inevitable one. Bitcoins (the actual units of this virtual currency) are a form of electronic money that can be traded directly between parties; do not require the physical backing of gold, dollars, or any other traditional store of value; and whose price is based on demand over a peer-to-peer network. That isn't that different from mainstream currencies -- since the abolition of the gold standard in the 1970s and the creation of floating exchange rates, even the U.S. Dollar functions mostly on the same principles.

????The big difference? Regulation. Unlike cash, bitcoin isn't backed by a central bank, which essentially gives conventional currencies their real value.

????To understand this, consider that a shopkeeper sells a candy bar to a customer for a fixed price. The customer knows before he walks in that the dollars in his pocket will yield a certain amount of value. That value (the price of the dollar) might fluctuate in foreign exchange markets but only within a narrow band and will not affect the ability of the customer to buy the candy bar in real time. If the value of the dollar fluctuates too far out of an acceptable range, it will usually be brought back in line through currency transactions by central banks. That's precisely why a fiat currency system (not pegged to gold) can still work and not be disrupted because of currency speculators.

????By contrast, the volatility of bitcoin makes everything a lot less certain. Neither the shopkeeper nor the customer would know how to correctly price the candy bar at any given time, since the value of the virtual currency undergoes such extreme highs and lows. Over the past year, the price of a bitcoin has gone from $14 to more than $1,100, settling back down around $500 at the end of 2013. The fluctuations not only make predictability of value impossible but also render bitcoins almost worthless. The reason for this is that bitcoins, due to their lack of any official anchor, exist only in the context of barter or speculation, and when the transactions and hype stop, so does the music. In other words, the success of bitcoin is based on a self-fulfilling prophecy, which is just as dangerous as it sounds and does not even pass the test for a real currency.

????There is also the small problem of bitcoins being irreplaceable, a case in point being a man who lost some $7.5 million worth of bitcoins because he threw away a hard drive. Cash can be misplaced too, of course, but hardly in such quantities and so easily. This factor, combined with the issues mentioned above, makes bitcoin an extremely unreliable medium of exchange, which detracts from its value proposition: anonymity, tax free transactions, and low transaction costs compared to credit cards.

????Finally, there is Silk Road, the online marketplace for illegal goods shut down by U.S. authorities and facilitated by bitcoin. The popularity of bitcoin for conducting illegal trade due to its anonymous nature and peer-to-peer system might bode well for bitcoin investors but is almost sure to attract fire from law enforcement sooner or later (Silk Road being one example) and could result in heavy restrictions being placed on its usage. This week at the World Economic Forum in Davos, U.S. financial leaders shared a similar outlook on bitcoin: "The question isn't whether we accept it," JPMorgan (JPM) CEO Jamie Dimon told CNBC. "The question is do we even participate [with] people who facilitate bitcoin? The people who are going to eventually really get upset with it will be governments."