1) Irreversible: After confirmation, a transaction can‘t be reversed. By nobody. And nobody means nobody. Not you, not your bank, not the president of the United States, not Satoshi, not your miner. Nobody. If you send money, you send it. Period. No one can help you, if you sent your funds to a scammer or if a hacker stole them from your computer. There is no safety net.

As can be seen from the data on this page, Ethereum’s price has been enormously volatile and therefore highly unpredictable over the short-term. However, longer-term trends are easier to predict, with fundamental metrics such as the total number of developers, community discussion and GitHub pull requests indicating a more accurate future price trend. Other methods to predict the price of Ethereum include metrics such as Network Value to Transaction ratio (NVT ratio) and the relative prices between coins. The method that we find most interesting is in that of the Ethereum-based prediction market, Augur. These predictions source the “wisdom of the crowd” to determine the likelihood of an outcome occurring and provide a significant level of insight into the market sentiment.
Many uses have been proposed for Ethereum platform, including ones that are impossible or unfeasible.[46][33] Use case proposals have included finance, the internet-of-things, farm-to-table produce, electricity sourcing and pricing, and sports betting. Ethereum is (as of 2017) the leading blockchain platform for initial coin offering projects, with over 50% market share.

In October 2015,[62] a development governance was proposed as Ethereum Improvement Proposal, aka EIP, standardized on EIP-1.[63] The core development group and community were to gain consensus by a process regulated EIP. A few notable decisions were made in the process of EIP, such as EIP-160 (EXP cost increase caused by Spurious Dragon Hardfork)[64] and EIP-20 (ERC-20 Token Standard).[65] In January 2018, the EIP process was finalized and published as EIP-1 status turned "active".[62] Alongside ERC-20, notable EIPs to have become finalised token standards include ERC-721[66] (enabling the creation of non-fungible tokens, as used in Cryptokitties) and as of June 2019, ERC-1155 [67] (enabling the creation of both fungible and non-fungible tokens within a single smart contract with reduced gas costs).
As can be seen from the data on this page, Ethereum’s price has been enormously volatile and therefore highly unpredictable over the short-term. However, longer-term trends are easier to predict, with fundamental metrics such as the total number of developers, community discussion and GitHub pull requests indicating a more accurate future price trend. Other methods to predict the price of Ethereum include metrics such as Network Value to Transaction ratio (NVT ratio) and the relative prices between coins. The method that we find most interesting is in that of the Ethereum-based prediction market, Augur. These predictions source the “wisdom of the crowd” to determine the likelihood of an outcome occurring and provide a significant level of insight into the market sentiment.
An initial coin offering (ICO) is a controversial means of raising funds for a new cryptocurrency venture. An ICO may be used by startups with the intention of avoiding regulation. However, securities regulators in many jurisdictions, including in the U.S., and Canada have indicated that if a coin or token is an "investment contract" (e.g., under the Howey test, i.e., an investment of money with a reasonable expectation of profit based significantly on the entrepreneurial or managerial efforts of others), it is a security and is subject to securities regulation. In an ICO campaign, a percentage of the cryptocurrency (usually in the form of "tokens") is sold to early backers of the project in exchange for legal tender or other cryptocurrencies, often bitcoin or ether.[47][48][49]
If you decide to invest in cryptocurrencies, Bitcoin is obviously still the dominant one. However, in 2017 its share in the crypto-market has quite dramatically fallen from 90 percent to just 40 percent. There are many options currently available, with some coins being privacy-focused, others being less open and decentralized than Bitcoin and some just outright copying it.
As of February 2018, the Chinese Government halted trading of virtual currency, banned initial coin offerings and shut down mining. Some Chinese miners have since relocated to Canada.[32] One company is operating data centers for mining operations at Canadian oil and gas field sites, due to low gas prices.[33] In June 2018, Hydro Quebec proposed to the provincial government to allocate 500 MW to crypto companies for mining.[34] According to a February 2018 report from Fortune,[35] Iceland has become a haven for cryptocurrency miners in part because of its cheap electricity. Prices are contained because nearly all of the country's energy comes from renewable sources, prompting more mining companies to consider opening operations in Iceland.[citation needed]
Darknet markets present challenges in regard to legality. Bitcoins and other forms of cryptocurrency used in dark markets are not clearly or legally classified in almost all parts of the world. In the U.S., bitcoins are labelled as "virtual assets". This type of ambiguous classification puts pressure on law enforcement agencies around the world to adapt to the shifting drug trade of dark markets.[75]
In 2016 a decentralized autonomous organization called The DAO, a set of smart contracts developed on the platform, raised a record US$150 million in a crowdsale to fund the project.[25] The DAO was exploited in June when US$50 million in ether were taken by an unknown hacker.[26][27] The event sparked a debate in the crypto-community about whether Ethereum should perform a contentious "hard fork" to reappropriate the affected funds.[28] As a result of the dispute, the network split in two. Ethereum (the subject of this article) continued on the forked blockchain, while Ethereum Classic continued on the original blockchain.[29] The hard fork created a rivalry between the two networks.
NEM — Unlike most other cryptocurrencies that utilize a Proof of Work algorithm, it uses Proof of Importance, which requires users to already possess certain amounts of coins in order to be able to get new ones. It encourages users to spend their funds and tracks the transactions to determine how important a particular user is to the overall NEM network.

Though each bitcoin transaction is recorded in a public log, names of buyers and sellers are never revealed – only their wallet IDs. While that keeps bitcoin users’ transactions private, it also lets them buy or sell anything without easily tracing it back to them. That’s why it has become the currency of choice for people online buying drugs or other illicit activities.
Wallets and similar software technically handle all bitcoins as equivalent, establishing the basic level of fungibility. Researchers have pointed out that the history of each bitcoin is registered and publicly available in the blockchain ledger, and that some users may refuse to accept bitcoins coming from controversial transactions, which would harm bitcoin's fungibility.[128] For example, in 2012, Mt. Gox froze accounts of users who deposited bitcoins that were known to have just been stolen.[129]
^ Iansiti, Marco; Lakhani, Karim R. (January 2017). "The Truth About Blockchain". Harvard Business Review. Harvard University. Retrieved 17 January 2017. The technology at the heart of bitcoin and other virtual currencies, blockchain is an open, distributed ledger that can record transactions between two parties efficiently and in a verifiable and permanent way.
According to the Library of Congress, an "absolute ban" on trading or using cryptocurrencies applies in eight countries: Algeria, Bolivia, Egypt, Iraq, Morocco, Nepal, Pakistan, and the United Arab Emirates. An "implicit ban" applies in another 15 countries, which include Bahrain, Bangladesh, China, Colombia, the Dominican Republic, Indonesia, Iran, Kuwait, Lesotho, Lithuania, Macau, Oman, Qatar, Saudi Arabia and Taiwan.[178]

Miners are the single most important part of any cryptocurrency network, and much like trading, mining is an investment. Essentially, miners are providing a bookkeeping service for their respective communities. They contribute their computing power to solving complicated cryptographic puzzles, which is necessary to confirm a transaction and record it in a distributed public ledger called the Blockchain.
In October 2015,[62] a development governance was proposed as Ethereum Improvement Proposal, aka EIP, standardized on EIP-1.[63] The core development group and community were to gain consensus by a process regulated EIP. A few notable decisions were made in the process of EIP, such as EIP-160 (EXP cost increase caused by Spurious Dragon Hardfork)[64] and EIP-20 (ERC-20 Token Standard).[65] In January 2018, the EIP process was finalized and published as EIP-1 status turned "active".[62] Alongside ERC-20, notable EIPs to have become finalised token standards include ERC-721[66] (enabling the creation of non-fungible tokens, as used in Cryptokitties) and as of June 2019, ERC-1155 [67] (enabling the creation of both fungible and non-fungible tokens within a single smart contract with reduced gas costs).
Ethereum was initially described in a white paper by Vitalik Buterin,[10] a programmer involved with Bitcoin Magazine, in late 2013 with a goal of building decentralized applications.[11][12] Buterin had argued that Bitcoin needed a scripting language for application development. Failing to gain agreement, he proposed development of a new platform with a more general scripting language.[4]:88

^ "Bitcoin: The Cryptoanarchists' Answer to Cash". IEEE Spectrum. Archived from the original on 4 June 2012. Around the same time, Nick Szabo, a computer scientist who now blogs about law and the history of money, was one of the first to imagine a new digital currency from the ground up. Although many consider his scheme, which he calls "bit gold", to be a precursor to Bitcoin
On 3 January 2009, the bitcoin network was created when Nakamoto mined the first block of the chain, known as the genesis block.[25][26] Embedded in the coinbase of this block was the text "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks".[16] This note references a headline published by The Times and has been interpreted as both a timestamp and a comment on the instability caused by fractional-reserve banking.[27]:18
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