The NEM blockchain powers what they call the Smart Asset System. This system is intended to be an open, customizable blockchain solution for any number of use cases built on top of simple, powerful API calls. The blockchain is secured and transactions are processed by a global network of nodes running the NEM core software, and the network is used as an API Gateway server.
NEM has gone through extensive open alpha testing starting June 25, 2014, followed by lengthy and comprehensive beta testing starting on October 20, 2014. NEM finally launched on May 31, 2015.