It is an old alt and a dump time is finished in 2014.
The idea of developing NVC-antispam mechanism is to increase the costs of sending spam and make it ineffective. With each message the digital stamp (a small payment from NVC PoS reward) is sent, and the proof of payment is attached to the message. Messages without this stamp are considered as a spam, and the optional reply can be forwarded to the sender, explaining why his message was rejected. There also a whitelist where legitimate senders could be added manually so that they don't require a stamp.