To put it into modern terms, think of a Croquet world as a peer-to-peer 3-D Slack channel that anybody could host as easily as a web page. It used TeaTime and two-phase commit for low-latency synchronization, making it a distributed, real-time database of sorts. And what it distributed were objects and events, so maybe also think of it like Ethereum contracts, where the members' VMs together constitute the execution engine.

Croquet was and still is far ahead of its time. Only in 50 or 100 years will people realize the potential, at which point Croquet itself will likely have been forgotten completely :(