Clique is the Proof of Authority consensus algorithm on the Rinkeby testnet. In Clique, only an approved list of signers can produce/seal blocks. The approved signer list is dynamic and current signers can vote to add or remove other members. For this reason, PoA emphasizes the importance of identity and reputation in the network. PoA is a visual reputation of Clique as x0r's fingerprint, signifying identity, composed of the "clique.go" and "snapshot.go" source code from go-ethereum.
