The internet has given birth to an expanding number of shared virtual reality spaces, with a collective population well into the millions. These virtual worlds exhibit most of the traits we associate with the Earth world: economic transactions, interpersonal relationships, organic political...

In March 1999, a small number of Californians discovered a new world called "Norrath", populated by an exotic but industrious people. About 12,000 people call this place their permanent home, although some 60,000 are present there at any given time. The nominal hourly wage is about USD 3.42 per...

Several million people currently have accounts in massively multi-player online games, places in cyberspace that are effectively large-scale shared virtual reality environments. The population of these virtual worlds has grown rapidly since their inception in 1996; significantly, each world also...

How has innovative and competitive behavior in computing and Internet markets evolved over the past half-century? In the first section of this review, I discuss these questions in light of six topics: the limited role for technology push; the diffusion of general-purpose technologies; the...