Bitcoin miners are firstly looking for reward blocks, and then secondly backing up the network.  The word "miner" is good because it shows that they are randomly trying to get gold (bitcoin).

But in our system people that run a node can't have their primary goal be to earn fees.  NXT has run into this problem.  From a economic perspective, forging in NXT is a losing game.  Most people that are not original founders of NXT will not earn enough fees from NXT to pay for electricity.  Why?  Because there are no block rewards, but instead only transaction fees.  

The main motivation behind forging/mining in NEM should be to protect our stakes.  As stakeholders, if we don't run nodes, then the network will fall apart.  I think a word for forging/mining in  POI system should emphasis, not the rewards from fees, but the fact that a person running a node is vested in protecting the network from attack.  

Something like "gating" or "guarding" is literally more what is happening.  

I like a word more like "backing" though.  As "backers" a person is "backing up" the network, but also getting NEM "back" as a reward.  Additionally, "backers" would be the "backbone" of the network.

Can anybody else think of a word that focuses on maintaining the network but also infers getting a reward?