DegDB ("Distributed Economic Graph Database") is a graph database management system where every request has either a debit (with attached bitcoin) or a credit (with bitcoin promised on delivery) payment system. The DBMS's server nodes estimate how much it will cost to serve the data; if there is not enough bitcoin attached to service the request, then the node will drop the request.
https://docs.google.com/document/d/1Z1zUMOGzsBLOU1JoeY-CLFI9eSMajrnQraBvSybjP8I/edit
Tristan Rice
2015