Golem - worldwide supercomputer
Ethereum is branded as 'the World Computer", but, according to Golem developers, it is still more directed to building consensus, etc. and not for large scale distributed computing. Therefore they started to develop Golem as a distributed computer, but using Ethereum for micropayments for processes.
It seems that Golem solves a problem of Ethereum that allows computing processes to pay for the computing resources, if not by completely decentralized architecture, then at least by having a centralized process which could distribute the process.
Whitepaper - "A Probabilistic Nanopayment Scheme for Golem";