Proof of Stake (PoS) is a consensus mechanism aimed to safeguard the integrity of a blockchain network and authenticate transactions. It can be likened to a voting system where participants' voting power is determined by the number of coins they possess and are willing to "stake" or lock up.

Proof of Work, is dependable on computational power, while Proof of Stake operates based on the concept of ownership. The more coins a participant has and is willing to stake, the greater their chances of being selected as a validator for a new block.

Validators play a vital role in the blockchain ecosystem by ensuring the validity of transactions and their inclusion in the blockchain ledger. As a reward for their active participation, validators receive additional coins. PoS is recognized for its energy efficiency in contrast to Proof of Work and encourages participants to retain and support the network by staking their coins.