An Immstruct structure can hook onto the next-animation-frame event and then get itself rendered so that in the demo examples you are actually hooking the structure into the app event loop and the rendering is being driven by the data structure's events.
Seems clever but I can't say it is intuitive. Following the logic seems to require a fair degree of both Om and React knowledge.
There is a function called component that seems to be wrapping React.createClass so you don't need the bulk of the Component boilerplate.
Omniscient is based on top of ImmutableJS and has created a library called Immstruct that wraps Immutable with the ability to create cursors on the structures and also an event framework.
The project doesn't seem to have a sensible tutorial or introduction.