I've posted on mapping a few times now - with the previous post disucssing the 3D Second Life virtual world. With social networks, mash-ups, and environmental maps/sensors, there is a trend towards converging global information flows with visual representations.
In a post from Worldchanging:
"The new converging tools are bound to be powerful, transforming the ways we see and work in the physical world just as much as the mutate the ways we interact online.
They're also much needed. As global pressures mount, and we begin to have to take more seriously the work of managing the planet, being able to imagine the implications of both the challenges we face and the better futures we're working towards creating will prove vital."
This post refers to the Metaverse Roadmap Project - worth a look...