From Second Life Sketches: Two Worlds - Fame and Infamy:
It’s the biggest digital art installation in the world, the size of eight Manhattan Islands, but there are never more than 20,000 people there at the same time. It’s an instant messaging system, a software-coding environment, a design platform for 3-D architecture, an online community, and, conceivably, the germ of the next generation of computer operating systems. It’s called Second Life.