The beauty of cryptocurrency like Ethereum is decentralized storage based on peer-to-peer cryptography. Because the whole database is stored in each node (specifically, in a software called Ethereum Virtual Machine, or EVM), malicious cyberattacks or government seizure on any particular node or nodes will not impact the whole database.
You are probably aware that there are tons of cryptos out there. One of the main distinctions between different cryptos is the consensus mechanism which every crypto is built upon. “consensus mechanism,” at its core, is the consensual rule that a specific community follows. Based on the consensus mechanism, each node (computer) can confirm a piece of specific information in the database (i.e., a block) or reject a request for a record. The node will broadcast its confirmed block to the nodes of the network for validation. Finally, all confirmed blocks form the “blockchain.”
Two main consensus mechanisms are Proof of Work (PoW) and Proof of Stake (PoS). Simply put, PoW is a first-come-first-serve rule – whichever node correctly confirms the information first takes all the rewards. Because it is a first-come-first-serve rule, it is energy-intensive, or even energy inefficient. In contrast, PoS is like a shareholder-variant rule. The more cryptos (i.e., ETH) a node deposits in the pool, the more likely the node can get the opportunity to validate the information and get a reward, or it may get penalized if such recordation is proved wrong. You can see more comparisons between PoS and PoW here (CoinMarketCap), here (Cointelegraph), and here(Investopedia).
Ethereum was officially launched on 30 July 2015. The consensus mechanism of Ethereum had been PoW until its recent upgrade called “Merge,” in which Ethereum transitioned from PoW to PoS.
Since PoS is a shareholder-variant rule, let’s take a look at the shareholder registrar of Ethereum, so to speak: