[bai0]

Have you checked out JanusVR? It's pretty much what you're describing. Its web client, native client, and server are all open source. Anyone can create worlds and host them like you would any other website, and links between sites are represented as portals.

For a sampling of some of the worlds people have built, check out https://vesta.janusvr.com/

[heyitsguay]

Interesting, thanks for sharing! So what are the features a big company like Facebook can offer over e.g. JanusVR? Asset generation? Network effects? Does JanusVR have anything like a killer app?