The first decentralized supercomputer was SETI@HOME by 17-05-1999. It was later migrated to BOINC platform, which was created in 10 April 2002 in order to support other science computing projects. In 16 October 2013 Gridcoin was created, a cryptocurrency whose Proof of work mechanism is based in collaboration with BOINC projects.
Info:
http://gridcoin.us/
https://setiathome.berkeley.edu/
https://boinc.berkeley.edu/
RE: The Golem Project Overview (GNT)