Second Life is an online virtual world developed by Linden Lab. It was launched on June 23, 2003. A number of free client programs, or Viewers, enable Second Life users, called Residents, to interact with each other through avatars. Residents can explore the world (known as the grid), meet other residents, socialize, participate in individual and group activities, and create and trade virtual property and services with one another. Second Life is intended for people aged 16 and over. The game reached its top popularity in the mid-to-late 2000s,when major pop-rock acts (Duran Duran, Depeche Mode), politician and showbiz personalities made virtual appearances, concerts and public speeches on Second Life, but it has since declined, as other competing clients have appeared mimicking SL appearance and setup.

Built into the software is a three-dimensional modeling tool based on simple geometric shapes that allows residents to build virtual objects. There is also a procedural scripting language, Linden Scripting Language, which can be used to add interactivity to objects. Although sculpted prims (sculpties), mesh, textures for clothing or other objects, and animations and gestures can be created using external software and imported, all such options require extensive programming skills making Second Life a complex game, best experienced by people with beyond-average computer gaming knowledge. The Second Life Terms of Service provide that users retain copyright for any content they create, and the server and client provide simple digital rights management functions.