The computer accesses a computer-simulated world and presents perceptual stimuli to the user, who in turn can manipulate elements of the modeled world and thus experiences telepresence to a certain degree. Such modeled worlds may appear similar to the real world or instead depict fantasy worlds. The model world may simulate rules based on the real world or some hybrid fantasy world. Example rules are gravity, topography, locomotion, real-time actions, and communication. Communication between users has ranged from text, graphical icons, visual gesture, sound, and rarely, forms using touch, voice command, and balance senses.
Massively multiplayer online games commonly depict a world very similar to the real world, with real world rules and real-time actions, and communication. Communication is usually textual, with real-time voice communication using VOIP also possible.[clarification needed]
Virtual worlds are not limited to games but, depending on the degree of immediacy presented, can encompass computer conferencing and text based chatrooms. Sometimes, emoticons or 'smilies' are available, to show feeling or facial expression. Emoticons often have a keyboard shortcut. Edward Castronova is an economist who has argued that "synthetic worlds" is a better term for these cyberspaces, but this term has not been widely adopted.