Open Source 3D Worlds

Or so the Wiki says (via Chris Hanson). The Croquet Consortium is an open source software foundation that has put together Croquet:

Croquet is a powerful open source software development environment for the creation and large-scale distributed deployment of multi-user virtual 3D applications and metaverses that are (1) persistent (2) deeply collaborative, (3) interconnected and (4) interoperable. The Croquet architecture supports synchronous communication, collaboration, resource sharing and computation among large numbers of users on multiple platforms and multiple devices.

Which is what exactly? The 3D web? A place like Second Life where the world is persistent (as long as the servers stay up)? No, according to the FAQ, it's a software development environment.

This certainly is interesting, and it's supported by the New Media Consortium which will help institutions build a virtual presence. Training, education, conferences? Is this the *.edu to Second Life's *.com built on Croquet (akin to linux)?