NEM (XEM)

“NEM is a blockchain platform that was launched in March of 2015. At the time it was one of the pioneers of the industry and sought to improve on the imperfections found on other chains at the time. It was one of the first non-turing complete chains to feature user-defined tokens (called mosaics), namespaces, multisignature accounts, and a P2P reputation system based on EigenTrust++.

Its most notable contribution to the space is the proof-of-importance consensus mechanism, which sought to reward on-chain activity and deter the concentration of wealth commonly associated with proof-of-stake. Its client, NIS, is written in Java. 

Today, NEM sees the most utility as an alternative form of payment for businesses and vendors, and has a variety of applications built on top of it in Japan. Current development is centred around NEM’s merge with another blockchain platform: Symbol.”