IOTA (IOTA) is a distributed ledger for the Internet of Things that uses a directed acyclic graph (DAG) instead of a conventional blockchain.
Its quantum-proof protocol, Tangle, reportedly brings benefits like 'zero fees, infinite scalability, fast transactions, and secure data transfer'.
The IOTA Tangle is a Directed Acyclic Graph which has no fees on transactions and no fixed limit on how many transactions can be confirmed per second in the network; instead, the throughput grows in conjunction with activity in the network; i.e., the more activity, the faster the network.