NoSQL existed already in 1966 ...
IMHO, the first NoSQL system which is widely used today for such a long time, was developed already in 1966 (!) by Octo Barnett, Neil Pappalardo, Robert Greenes, and Curt Marble. In 1967, they developed the M language with the associated key/value storage engine. Unfortunately, this NoSQL system still remains one of the best kept secrets in industry as it is so widespread in healthcare and financial services. This group of inventors deserve a place in the list of NoSQL pioneers!
Today, the original M language exists in mainly two forms: the commercial variant Caché (developed by InterSystems) and the open-source variants GlobalsDB and GT/M (developed by FIS / Greystone Technology Corp).
Since Terry Ragon founded the company InterSystems in 1978, the original database has undergone a major transformation during the last 20 years to the leading Caché product it is today, making it one of the most powerful and scalable databases in the world. Caché has a unified data architecture and allows you to acces your data in different ways (key/value pairs, object access and SQL) without the need to write projections or mapping code. In addition, Caché seamlessly integrates with all kinds of environments, including e.g. the currently very popular Node.js technology (widely used for NoSQL applications) using the EWD.js framework.