The total stake of a pool consists of ADA coins of the pool operator (pledge) and delegated ADA coins. Pledge can be considered the oprator's skin in the game. There is a parameter in the protocol that affects the effect of pledge on rewards. If the operator puts his own coins into the pool in the form of pledge, the total stake of the pool increases. The pledge can be 0 and the pool can only rely on ADA coins delegated by the stakers. Alternatively, the pool operator can delegate coins to itself on its own pool. The pledge is an important signal to the stakers, as they can see that the pool operator has staked his coins on the success of his pool. The operator receives a reward for the pledge similar to that of staked ADA coins. If the pool receives no reward in the epoch, the operator will not receive a reward for staked ADA coins in the form of pledge. Pools with higher pledge may be considered more attractive by stakers. It is desirable for the network to be run by people who are willing to invest their own assets to show goodwill in doing quality work for the protocol. On the other hand, a high pledge requirement could discourage less wealthy individuals from starting new pools.
