These MMORPGs are based on real life. The virtual world copies the real world and is constructed by its residents (the players). Players can use voice and text chat to communicate with other real people in a way closer to social networking than other MMORPGs. The virtual world is inhabited by a resident population of thousands/millions of real people from around the world. Each person is represented by an avatar, their chosen digital persona. These games provide more and more freedom to their residents, who can be very creative (create a business, hang out with friends in a night club, build a house, etc.).
Second Life is a 3D virtual world entirely built and owned by its
participants. Since opening to the public in 2003, it has grown
explosively and today is inhabited by more than 6,700,000 residents
from around the globe. More than a game, SL is like an interface
from real life to cyber creations. See also this forum, and
these Star Wars fans within Second Life.