What is Virtual World? Day by day technology is become more powerful. As the improvement of technology , we can hope that the idea of virtual world can come true in this new year. A virtual world is a computer-based simulated environment that users can inhabit and in which they interact with others either as themselves or through software agents (bots) or graphical representations called avatars. Due to the limited computational power and network resources available on today’s machines, virtual worlds are often implemented using 2D graphics with simple physics and AI engines. However, as computers become more powerful, virtual-world designers are using 3D graphics and more sophisticated algorithms. Types Of virtual world Three-dimensional virtual worlds can be broadly classified into online games and metaverses. Online games have been around for over a decade. Some—for example, first-person shooters like Quake—are designed to let a small group (up to tens of users) play together. Massively multiplayer online games (MMOGs) are designed to scale from hundreds to thousands of players simultaneously. Most online games rely on the client-server model, in which each user runs a client program that connects to one or more machines that run the server program. Meta-universes, or metaverses, are fully immersive virtual spaces that significantly differ from online games in several ways. Key Features of a Virtual World : That may be implemented in new year ? A virtual world must support a broad range of client machines from high-end gaming desktops to ultramobile PCs. ? A virtual world’s servers are connected to high band-width links while client are connected to lower band-width links. ? A virtual world must accurately represent users, in the form of avatars as well as object such as buildings,terrain and trees Software architecture for virtual world In recent year there are many research has already been done that how the software of virtual world will be designed. A recent research propose a design where Second Life users run a client program that connects to a central server, which employs three main clusters of machines. The data servers manage a central database, a logging database, an inventory database, and a search database. Another collection of servers simulates the virtual world as it evolves over time. Finally, a small number of machines perform utility functions like user authentication during login and instant messaging during sessions. Finally we can say that Unlike traditional online games, metaverses like Second Life must dynamically provide content—which is mostly user-generated and continually modified—to users depending on their location in the virtual world. So we can expect that as virtual worlds evolve to support more users, types of interactions, and realism, these demands will increase by orders of magnitude in new year