The NEM Supernode's program is funded with XEM set aside during the Nemesis block. These awards are then given to high performance nodes for helping to secure the network. These nodes form a backbone of support for light wallets, mobile wallets, and 3rd party apps so that users of these services might have access to the network that is easy, fast, and reliable without having to sync a blockchain by themselves or use untrustworthy centralized services.
The NEM network has been designed from the very beginning with the goal in mind that any light client can securely connect to and use any server safely to make any transaction. Supernodes are expected to be high performance and reliable nodes. They are regularly tested on their bandwidth, chain height, chain parts, computing power, version, ping, and responsiveness to make sure that they are performing to high standards. If they meet all these requirements, they are given rewards daily.
Rewards for the Supernodes program started on June 1st, 2016. The payout started at 70,000 XEM per day and will be split among all nodes that pass the tests for the day. This payout is planned to be increased at regular increments. In the event of a Supernode’s program update and/or downtime of the Supernode’s monitor, rewards will not be paid for that day.
FAQ and more http://blog.nem.io/supernodes-start/
