A virtual world (VW) is a computer-basedcommunity shared by visitors. The virtual world always exists, regardless of whether visitors are logged into it or not. Visitors are represented by avatars that they control and can perform certain actions and interactions. The avatars are controlled by keyboard, computer mouse or other input devices.
The visitors or avatars of a virtual world can interact with each other in this simulated, user-defined environment via text or graphics-basedinformation, or via voice, audio, and video. The simulated environment can be two- or three-dimensional in which the visitors represented by the avatars appear. Through the computers that have access to this computer-simulated world, visitors can trigger actions, make changes in the modeled world, and appear in mixed reality ( MR) using telepresence.
Virtual worlds are purpose-driven. They can be focused on gaming or social, education, commerce, or for other purposes. All virtual worlds are characterized by persistence, interactivity, and synchronicity. The latter provides the necessary conditions for synchronous communication without loss of time.
Examples of virtual worlds are Second Life and World of Warcraft.