The shortcomings of the Bitcoin technical architecture have led others to propose and create alternative versions that differ in important ways, such as how transactions are confirmed using different consensus mechanisms or algorithms (e.g., proof of work, proof of stake, etc.), the speed of transaction confirmation, the nature of the value/asset being exchanged, the confidentiality of transaction data, trusted nature of the participating entities (i.e., permissioned — or private — ledgers, and permissionless — or public — ledgers), customizability for business/market use cases, and so on.
We prefer the term “distributed ledger” to “blockchain,” because it affords architectural flexibility and supports the formation of businesses as “platforms.” It is this evolution beyond the current blockchain technology to alternative types of digital value exchange that will enable future scenarios in digital business.
Source: Prepare For A Multiple Blockchain World – Forbes