In Mark Shuttleworth's post "#6: Sensory Immersion" he mentions that the open source community needs to take the idea of Second Life and innovate.
An Open Source "Second Life" like virtual world would be very cool. Granted that anyone could take the code and make their own virtual world out of it. But, then what's the point? We would end up with 1,000 virtual worlds.
We would need to create some standardized protocols for this type of virtual system to run on; much the same as how the Web and HTTP run. Then the protocols could unite all the different servers into one huge virtual world. There could essentially be a distributed virtual world and anyone could take the standards and write their own server or client that plugs into it. It would basically work how the Internet/Web itself works except it would be another system on top of that.
This type of system could be the New Web! It would take the web and mold it into an entirely new world. If a client were written for it that implemented Virtual Reality you could actually walk around in this new world and be fully emmerse inside it.
Companies like Verisign could issue certificates that would certify objects and places in the virtual world as being what they appear to be. There could be all kinds of items created/sold inside the virtual world. A whole new economy could emerge within this virtual world.
In order for such a virtual world to succeed; standards would need to be written and there would need to be some governing body (similar to ICANN). The governing body couldn't be a for profit company since all they would see is $$$ instead of Standard Compliance.