Smart contracts on Ethereum are fully self contained and any information or access to off-chain data is restricted. Tellor solves this problem by creating a system where parties can request the value of an off-chain data point (e.g. ETH/USD) and miners compete to add this value to an on-chain data bank, accessible by all Ethereum smart contracts. Inputs to a data series are secured by a network of staked miners. The main Tellor smart contract creates a time series of each requested data series and aims to become the standard source of high value data for decentralized applications. This oracle, “Tellor”, utilizes similar incentive mechanisms to other cryptocurrency systems through the issuance of Tellor’s token, Tributes, that are used to request a particular data series from miners.
Metronome, found online at Metronome.io, under the symbol MTN. The cryptocurrency promises to deliver “institutional-class endurance” with cross-blockchain compatibility.The currency is being developed by Bloq, which announced Metronome in October 2017. Metronome is launched in early December 2017, with the first cross-chain transfers (between Ethereum and Ethereum Classic) scheduled for Q1 2018. Metronome released in December 2017. By Q1 2018, Metronome aims to become the world’s first cross-chain compatible cryptocurrency by adding Ethereum Classic support (the currency is initially built on Ethereum). Metronome’s cross-chain compatibility system involves creating exit receipts when leaving the chain and entering a new chain.