This chapter presents an introductory overview of virtual worlds. Its purpose is to give the reader a basic knowledge about what a virtual world is. It also discusses some open issues that, from the author’s point of view, should be taken into account when new virtual worlds, or new applications running over existing virtual worlds, are designed. The chapter provides a general definition of a virtual world, presents a historic review of these systems and describes the main features and elements that they are composed of. The chapter aims to be useful to the non-technical readers in that it shall provide a clearer concept of virtual worlds. In the case of technical readers, it attempts to be a reference for further research.
TopBut, What Is A Virtual World?
Nowadays, most people when ask what is a Virtual World is can give a more or less clear answer. This question prompts most to think about general purpose virtual worlds such as Second Life® or There, or perhaps game-oriented worlds like World of Warcraft.
In this manner, we think of concepts related to them, such as multiuser capabilities, sense of presence, etc.
But, the truth is that an universally accepted definition of Virtual World does not exist. That is, there is no existing agreement about the concrete features that compose a virtual world and, and therefore the characteristics that distinguish it from other applications. Instead of this, there are several existing definitions that maintain basic concepts but present little differences. In each of these definitions the group of systems that can be understood as virtual worlds changes.
Therefore, the first step in this chapter will be the review and study of different definitions of virtual words. Then, a definition that compiles the terms and concepts that specify a virtual world, as considered by this book, will be proposed.
Definitions of virtual world have evolved through the years, much in the same way that virtual worlds have also evolved. Perhaps, one of the first definitions that is closed to the modern concept of virtual worlds is the definition which was established by Klastrup in 2003 (Klastrup, 2003). From Klastrup’s point of view, a virtual world is a persistent on-line representation that offers the possibility of synchronous interaction between users, and between the users and the world, in the frame of a space designed as navigable universe.
In the same year, Bartle (Bartle, 2003) defined a virtual world as an environment where their inhabitants are auto-contented.
Both definitions –although the evolution of virtual worlds from 2003 should be highlighted- do not take into account important aspects of current virtual worlds.
In the case of Klastrup, the representation of users in a virtual world is not specified. That is, presence and co-presence features in the virtual world are not reflected –the fact that the user has the illusion of being immerse in the virtual world and sees the rest of the users immersed too. It could perhaps be deduced from the term ‘navigable universe’, but it is not clear. In the case of Bartle, the definition is quite general. According to this definition, a literal interpretation would class a videoconferencing system as a virtual world also.
More recently, other authors such as Castronova (Castronova, 2006) have defined virtual worlds as artistic spaces in the computer that have been designed to contain containing a large number of people. On the other hand, Spence (Spence, 2008) defines them as persistent, tridimensional and not game-oriented spaces, and he further contends that they are mainly social spaces.
Another case is the work of Schroeder. He distinguishes between virtual reality, collaborative features and virtual worlds (R. Schroeder, 2008). In Schroeder’s point of view, virtual reality is a computer generated viewer that allows users to have the illusion of being in an environment different to the environment where they are and to allow them interact with it; collaborative features are the virtual environments, that he defines as environments where users experiment with other users as present in the same environment and interact with them; and virtual worlds as online persistent spaces.
These definitions establish some common characteristics such as presence, persistence in the world, synchronous interaction, etc. but keep a social focus about virtual worlds.
The vision in the framework of this chapter is somewhat different. It is true that these environments have had a strong social focus until recent years –and in many cases it remains so-. However, there is a current trend foreseen by different European technological platforms that study the Future Internet. With this trend, virtual worlds will grow in functionality and services (Eiffel, 2009). That is, they will not be only social or leisure places, but they will become portals for accessing general purpose services.