Every mark is real
Mike, VRdojo
The island is 16 km across, generated rock first: geology, then erosion, then soil and trees on top. From this build its surface can be dug or filled at half-metre resolution, and the server keeps the edit, so a hole you dig today is there next week for anyone who walks past.
Items and bodies are placed at a grain of 2.5 mm. Everything is at real scale: a log is a log, a decimetre is a decimetre, and the player stands about 1.78 m tall.
There is one world. No shards, no instances. Who you see and how often you hear from them adapts to how crowded it is around you, but everyone online is on the same island.