To put it simply, cryptocurrency mining is a process of solving complex mathematical problems. Miners are essentially the cornerstone of any cryptocurrency network as they spend their time and computing power to solve those math problems, providing a so-called ‘proof of work’ for the network, which verifies Ether transactions. Besides that, miners are responsible for creating new Ether tokens through this process, as they receive rewards in Ether for successfully completing a proof of work task.
As more and more miners join in, the problems automatically become more difficult to solve, which means more time and computational power is required to solve them and the rewards become smaller. However, as Ether’s value keeps surging upwards, the rewards received by miners are still quite substantial. Moreover, many people see mining as an ideological incentive, a mean of directly supporting the network.