Types of Blockchains?

Private Blockchain - With private blockchains write permissions are centralized in one organization. Read permissions may be public or might be restricted depending on the intent of the controlling company. Examples include auditing, database management, and regulation compliance such as SOX and HIPAA. Current private blockchains under development include the Hyperledger project from the Linux Foundation, and the Gem Health network.

Consortium Blockchain - A consortium platform shares has most of the same benefits with private blockchain, which is efficiency and transaction privacy, but spreads the leadership outside of one company to trusted participants. With consortiums the consensus process is controlled by a pre-selected set of nodes, and the selected participants decide who has read access to the blockchain. Examples of consortiums are financial institutions and international aid organizations.

Public Blockchain - Public blockchains are slow and costly compared to a private blockchain but serves the purposes of having every transaction public while users maintain anonymity. Despite being slower and more expensive than other blockchains, due to low transaction costs and eliminated middlemen such as trust companies, they are considerably less expensive than current options. Examples include property records, energy distribution, and tamper resistant voting.