Second Life

Second Life is an online virtual world, developed and owned by Linden Lab and launched on June 23, 2003. By 2013, Second Life had approximately one million regular users, while at the end of 2017, the active users are over between 800,000 and 900,000.

The virtual world can be accessed freely via Linden Lab's own client programs or via alternative third-party viewers. Second Life users, also called residents, create virtual representations of themselves, called avatars, and are able to interact with places, objects and other avatars. They can explore the world (known as the grid), meet other residents, socialize, participate in both individual and group activities, build, create, shop, and trade virtual property and services with one another.

History
In 1999, Philip Rosedale formed Linden Lab with the intention of developing computer hardware to allow people to become immersed in a virtual world. In its earliest form, the company struggled to produce a commercial version of the hardware, known as "The Rig", which in prototype form was seen as a clunky steel contraption with computer monitors worn on shoulders. That vision changed into the software application Linden World, in which people participated in task-based games and socializing in a three-dimensional online environment. That effort eventually transformed into the better known, user-centered Second Life. Although he was familiar with the metaverse of Neal Stephenson's novel Snow Crash, Rosedale has said that his vision of virtual worlds predates that book, and that he conducted early virtual world experiments during his college years at the University of California, San Diego, where he studied physics.

In 2005 and 2006, Second Life began to receive significant media attention, including a cover story in BusinessWeek magazine featuring the virtual world and Second Life avatar Anshe Chung. By that time, Anshe Chung had become Second Life's poster child and symbol for the economic opportunities that the virtual world offers to its residents. At the same time, the service saw a period of exponential growth of its user base.

In May 2009, concurent users avreaged about 62,000, while in May 2010, it avreaged about 54,000.

In November 2010, 21.3 million accounts were registered, although the company has not made public any statistics regarding actual long-term consistent usage. However, Wagner James Au, who blogs and writes about Second Life, said in April 2013 that he had it on "good authority" that Second Life's actual active userbase is about 600,000.

Teen Second Life
Teen Second Life was a version of Second Life for teenagers, it was open on February 13, 2005 for people who is under 16 to use Second Life. On January 1, 2006, Teen Second Life's operating hours were increased to 24 hours a day, whereas it was previously open only from noon to 10pm Pacific Time.

It was closed on 2010, it is no longer accessed. People aged 13–15 are allowed onto the main Second Life grid only via a school project or other related program.

Until the teen turns 18, it will transfer into main Second Life.