What is Ether
Ethereum is a permissionless blockchain that any developer can use it to build his/her own blockchain distributed apps. To run Ethereum blockchain, you need some kind of payment to pay it to the network that hosts the blockchain and its transactions.
Ether is the fuel that runs Ethereum. It is a form of payment made by the clients of the platform to the machines executing the requested operations. To put it another way, ether is the incentive ensuring that developers write quality applications (wasteful code costs more), and that the network remains healthy (people are compensated for their contributed resources).
How are ethers created?
The total supply of ether and its rate of issuance was decided by the donations gathered on the 2014 presale. The results were roughly:
- 60 million ether created to contributors of the presale
- 12 Million (20% of the above) were created to the development fund, most of it going to early contributors and developers and the remaining to the Ethereum Foundation
- 5 ethers are created every block (roughly 15 seconds) to the miner of the block
- 2-3 ethers are sometimes sent to another miner if they were also able to find a solution but his block wasn't included (called uncle/aunt reward)
Note that after the Byzantium update is implemented, the mining and uncle reward is reduced to 3 ethers and 0.625-2.625 ethers, respectively.
Is the ether supply infinite?
No. According to the terms agreed by all parties on the 2014 presale, issuance of ether is capped at 18 million ether per year (this number equals 25% of the initial supply). This means that while the absolute issuance is fixed, the relative inflation is decreased every year. In theory, if this issuance was kept indefinitely then at some point the rate of new tokens created every year would reach the average amount lost yearly (by misuse, accidental key lost, the death of holders etc) and there would reach an equilibrium.
But the rate is not expected to be kept: sometime in 2018-2019 Ethereum will be switched from Proof of Work to a new consensus algorithm under development, called Casper that is expected to be more efficient and require less mining subsidy. The exact method of issuance and which function it will serve is an area of active research, but what can be guaranteed now is that (1) the current maximum is considered a ceiling and the new issuance under casper will not exceed it (and is expected to be much less) and (2) whatever method is ultimately picked to issue, it will be a decentralized smart contract that will not give preferential treatment to any particular group of people and whose purpose is to benefit the overall health and security of the network.
