This is a system that lets NIFE clone entire games. It allows for a few different things:
Games (such as Aliens) that can be played over and over without setting them up anew each time.
Single-player experiences, as well as some unique variations.
The single-player experience is probably going to be crucial for advertising NIFE. Being able to make MMOs is cool but there's way more people interested in making single-player text adventures.
Because it's still NIFE (which is designed for multiplayer out of the box), single player worlds could optionally have:
The ability to invite your friends to also play the same character you're playing (this would be available with all games)
Depending on what the Host rules, the ability to invite your friends in as separate characters to help you play the game. These can optionally have combat restricted or can purely be mobile ghosts or have other restrictions.
Migrate your characters into another person's world and vice-versa
Game Instancing as a whole actually doesn't look that hard to set up. I do need to comb the entire database for some stuff (like entity references) but the actual actions involved look easy to set up.
It will more than likely make it into NIFE before it's ready to be advertised.