You first said it wasn’t copied but then you said it’s duplicated to millions of computers. Whats the difference between copying and duplicating? Your description of creating a word doc then emailing it to someone and waiting for the updated version from them is from 1999….google docs let’s you work on live docs – problem solved. Question…if an honest entry mistake happens on the blockchain why would you want that recorded on millions of computers forever?
Even recent entrants like Uber and AirBnB are threatened by blockchain technology. All you need to do is encode the transactional information for a car ride or an overnight stay, and again you have a perfectly safe way that disrupts the business model of the companies which have just begun to challenge the traditional economy. We are not just cutting out the fee-processing middle man, we are also eliminating the need for the match-making platform.

Although blockchain can save users money on transaction fees, the technology is far from free. The “proof of work” system that bitcoin uses to validate transactions, for example, consumes vast amounts of computational power. In the real world, the power from the millions of computers on the bitcoin network is close to what Denmark consumes annually. All of that energy costs money and according to a recent study from research company Elite Fixtures, the cost of mining a single bitcoin varies drastically by location, from just $531 to a staggering $26,170. Based on average utility costs in the United States, that figure is closer to $4,758. Despite the costs of mining bitcoin, users continue to drive up their electricity bills in order to validate transactions on the blockchain. That’s because when miners add a block to the bitcoin blockchain, they are rewarded with enough bitcoin to make their time and energy worthwhile. When it comes to blockchains that do not use cryptocurrency, however, miners will need to be paid or otherwise incentivized to validate transactions.
Although blockchain can save users money on transaction fees, the technology is far from free. The “proof of work” system that bitcoin uses to validate transactions, for example, consumes vast amounts of computational power. In the real world, the power from the millions of computers on the bitcoin network is close to what Denmark consumes annually. All of that energy costs money and according to a recent study from research company Elite Fixtures, the cost of mining a single bitcoin varies drastically by location, from just $531 to a staggering $26,170. Based on average utility costs in the United States, that figure is closer to $4,758. Despite the costs of mining bitcoin, users continue to drive up their electricity bills in order to validate transactions on the blockchain. That’s because when miners add a block to the bitcoin blockchain, they are rewarded with enough bitcoin to make their time and energy worthwhile. When it comes to blockchains that do not use cryptocurrency, however, miners will need to be paid or otherwise incentivized to validate transactions.
In Charles Stross' 2013 science fiction novel, Neptune's Brood, the universal interstellar payment system is known as "bitcoin" and operates using cryptography.[227] Stross later blogged that the reference was intentional, saying "I wrote Neptune's Brood in 2011. Bitcoin was obscure back then, and I figured had just enough name recognition to be a useful term for an interstellar currency: it'd clue people in that it was a networked digital currency."[228]

2. That transaction must be verified. After making that purchase, your transaction must be verified. With other public records of information, like the Securities Exchange Commission, Wikipedia, or your local library, there’s someone in charge of vetting new data entries. With blockchain, however, that job is left up to a network of computers. These networks often consist of thousands (or in the case of Bitcoin, about 5 million) computers spread across the globe. When you make your purchase from Amazon, that network of computers rushes to check that your transaction happened in the way you said it did. That is, they confirm the details of the purchase, including the transaction’s time, dollar amount, and participants. (More on how this happens in a second.)


Double spending means, as the name suggests, that a Bitcoin user is illicitly spending the same money twice. With physical currency, this isn't an issue: Once you hand someone a greenback $20 bill to buy a bottle of vodka, you no longer have it, so there's no danger you could use that same $20 to buy lotto tickets next door. With digital currency, however, as the Investopedia dictionary explains, "there is a risk that the holder could make a copy of the digital token and send it to a merchant or another party while retaining the original."
Some wallets offer a 'Receive Money' functionality. When you earn Bitcoins by accepting them as a payment method on a more regular basis it comes in handy when you use a button called 'Create Payment Request'. Here you enter the Bitcoin amount the customer has to pay and it will show the corresponding QR-code automatically. This way the customer doesn't need to enter an amount which makes the payment for them more convenient. For this method you need to calculate the Bitcoin amount from your USD or EUR price before you can enter it for the QR-code to generate.

Every time a new transaction is initiated, a block is created with the transactions details and broadcast to all the nodes. Every block carries a timestamp, and a reference to the previous block in the chain, to help establish a sequence of events. Once the authenticity of the transaction is established, that block is linked to the previous block, which is linked to the previous block, creating a chain called blockchain. This chain of blocks is replicated across the entire network, and all cryptographically secured which makes it not only challenging, but almost impossible to hack. I say almost impossible because it would take some significant computational power to even attempt something like that. 
Derivatives are used in stock exchanges and are concerned with the values of assets. Smart contracts in the trading of stocks and shares could revolutionize current practices by streamlining, automating and reducing the costs of derivatives trading across the industry. Settlements could be completed in seconds rather than the three days that are needed at present. Using smart contracts, peer-to-peer trading will become a usual operation, resulting in a complete revolution in stock trading. Barclays and several other companies has already trialed a way of trading derivatives using smart contracts, but they came to the conclusion that the technology won’t work unless banks collaborate to implement it.

Earning bitcoin in this manner has some variables associated with it, like whether the business is accepting bitcoin directly or through Lightning micropayments. Options like this are important to consider for a business owner for reasons surrounding ease of use and level of privacy (Lightning micropayments are much more private and cheaper than transactions settled directly on the Bitcoin blockchain).
You also have private blockchains. These are often used for more niche purposes like a business managing data or interacting with its customers. For example, Northern Trust, the financial services firm created one with IBM that it’s been testing for more than a year to store data such as biometric information and other records. In June, it also won a patent for storing meeting notes on the blockchain.

The main reason we even have this cryptocurrency and blockchain revolution is as a result of the perceived shortcomings of the traditional banking system. What shortcomings, you ask? For example, when transferring money to overseas markets, a payment could be delayed for days while a bank verifies it. Many would argue that financial institutions shouldn't tie up cross-border payments and funds for such an extensive amount of time.
Though transaction fees are optional, miners can choose which transactions to process and prioritize those that pay higher fees.[69] Miners may choose transactions based on the fee paid relative to their storage size, not the absolute amount of money paid as a fee. These fees are generally measured in satoshis per byte (sat/b). The size of transactions is dependent on the number of inputs used to create the transaction, and the number of outputs.[3]:ch. 8
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