Example: I tell three friends that I'm thinking of a number between 1 and 100, and I write that number on a piece of paper and seal it in an envelope. My friends don't have to guess the exact number, they just have to be the first person to guess any number that is less than or equal to the number I am thinking of. And there is no limit to how many guesses they get.
In the financial world the applications are more obvious and the revolutionary changes more imminent. Blockchains will change the way stock exchanges work, loans are bundled, and insurances contracted. They will eliminate bank accounts and practically all services offered by banks. Almost every financial institution will go bankrupt or be forced to change fundamentally, once the advantages of a safe ledger without transaction fees is widely understood and implemented. After all, the financial system is built on taking a small cut of your money for the privilege of facilitating a transaction. Bankers will become mere advisers, not gatekeepers of money. Stockbrokers will no longer be able to earn commissions and the buy/sell spread will disappear.

When the algorithm was created under the pseudonym Satoshi Nakamoto—which in Japanese is as common a name as Steve Smith—the individual(s) set a finite limit on the number of bitcoins that will ever exist: 21 million. Currently, more than 12 million are in circulation. That means that a little less than 9 million bitcoins are waiting to be discovered.
“Unlike traditional currencies, which are issued by central banks, Bitcoin has no central monetary authority. Instead it is underpinned by a peer-to-peer computer network made up of its users’ machines, akin to the networks that underpin BitTorrent, a file-sharing system, and Skype, an audio, video and chat service. Bitcoins are mathematically generated as the computers in this network execute difficult number-crunching tasks, a procedure known as Bitcoin “mining”. The mathematics of the Bitcoin system were set up so that it becomes progressively more difficult to “mine” Bitcoins over time, and the total number that can ever be mined is limited to around 21 million. There is therefore no way for a central bank to issue a flood of new Bitcoins and devalue those already in circulation.”
Bob spread his spreadsheet diary over 5,000 computers, which were  all over the world. These computers are called nodes. Every time a transaction occurs it has to be approved by the nodes, each of whom checks its validity. Once every node has checked a transaction there is a sort of electronic vote, as some nodes may think the transaction is valid and others think it is a fraud.

Up to this day, Bitcoin uninterruptedly works as money one person pays another person for goods and services. Once Bitcoin is exchanged, the record of the transaction is publicly recorded onto a ledger known as the blockchain, which other Bitcoin users, known as miners, verify by putting those transactions into a block and adding it to the blockchain after Proof of Work (PoW).
As Bitcoin’s price hit the record $5,000 for the second time in 2017, there is probably no current investment opportunity more hyped up than cryptocurrencies and Blockchain technology. The general public and governing authorities are increasingly more aware of its advantages, and most concerns surrounding it are being refuted. A lot of companies have already invested in the technology, and it is very telling that the worldwide technology giant IBM is now considering investing “employee time and energy” into the space.
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.
Because advertisers usually want to partner with top-ranked members, and since the forum increases its members’ rank based off their activity, Bitcointalk makes it nearly impossible for them to spam their way up from the lowest rank of Newbie to the highest rank of Legendary Member. The only way you can increase your rank and earn free bitcoins is by providing a high quantity of high quality posts.
However, trading Bitcoin successfully is not a matter of luck or guesswork. Profitable traders spend a substantial amount of time learning how to trade and how to overcome the many risks involved with trading. Successful traders know they might lose money in the short term but they look at it as an investment in their education, since they are aiming for the long term.

Rewards programs are a good use of cryptocurrencies, specifically tokens of the modern epoch, and one that might keep on giving is one that pays in Bitcoin. A network called BitcoinGet has a shopping service called CoinRebates which has a few major retailers including Walmart and Newegg within its network. You earn a varying amount of “bits” (100 satoshi = 1 bit) per dollar spent at each of the retailers. Walmart and others have in-store pickup, so you can effectively do your regular shopping and get a small Bitcoin rebate on it. Over time, this could really build up.

Consumers increasingly want to know that the ethical claims companies make about their products are real. Distributed ledgers provide an easy way to certify that the backstories of the things we buy are genuine. Transparency comes with blockchain-based timestamping of a date and location — on ethical diamonds, for instance — that corresponds to a product number.

Computing power is often bundled together or "pooled" to reduce variance in miner income. Individual mining rigs often have to wait for long periods to confirm a block of transactions and receive payment. In a pool, all participating miners get paid every time a participating server solves a block. This payment depends on the amount of work an individual miner contributed to help find that block.[86]

To lower the costs, bitcoin miners have set up in places like Iceland where geothermal energy is cheap and cooling Arctic air is free.[201] Bitcoin miners are known to use hydroelectric power in Tibet, Quebec, Washington (state), and Austria to reduce electricity costs.[200][202][203][204] Miners are attracted to suppliers such as Hydro Quebec that have energy surpluses.[205] According to a University of Cambridge study, much of bitcoin mining is done in China, where electricity is subsidized by the government.[206][207]
The receiver of the first bitcoin transaction was cypherpunk Hal Finney, who created the first reusable proof-of-work system (RPOW) in 2004.[22] Finney downloaded the bitcoin software on its release date, and on 12 January 2009 received ten bitcoins from Nakamoto.[23][24] Other early cypherpunk supporters were creators of bitcoin predecessors: Wei Dai, creator of b-money, and Nick Szabo, creator of bit gold.[25] In 2010, the first known commercial transaction using bitcoin occurred when programmer Laszlo Hanyecz bought two Papa John's pizzas for 10,000 bitcoin.[26]