Massively Distributed Virtual Worlds
The Internet is a Big place. So why is that every self claimed Massive Multiplayer Online Game feels small after a while. Game worlds aren't small when measured by square mile of simulated landscape. Games like World of Warcraft have vast space. When measured by new information, connectivity and extensibility these simulated places feel tiny. Only a handful of designers and graphic artists can build more of the world, or script more collaborative dance dance revolution scenarios (raids).
A Protocol for Walking Between Worlds
Second life has done a stand up job of updating their technology, but extensibility is limited. I can't build my own node, with potentially dramatically different visualizations without using their software and following their economic rules. Single company solutions are echoes of the past and bounded in their ability to grow: see MSN, AOL, and Facebook ok not yet they're still on the up-shwing.
Ideally each world will be rendered within the browser, bypassing the requirement for additional software installation (and licenses). The defining feature of distributed worlds, each node can be connected dynamically by their hosts, with no one company dictating the standard. There can be notions of neighborhoods, and real estate but that's up to independent organizations to determine. The Internet and Web have functioned superbly as information conduits because no one company controls the network. I see no reason why compatible 3D standards won't be equally as effective (WebGL*).
It wouldn't be too hard to come up with a model for all the elements necessary to support 3D virtual environments. Models could handle player identity, authorization, avatars, virtual gear/swag, and world building tools. Creation of virtual worlds could be easy for amateurs with rapid default layouts and choices (think blog themes), yet have deep customization features for master designers and world builders.
*= Thanks to Denny Gentry for pointing WebGL out to me. Hope he's not too sore about my bashing Google's bizarre hiring system on Buzz. Hey, they make a lot of bucks, and build big complicated stuff, what do I know?