Second Life is a virtual world where users create avatars to interact socially and participate in activities. It has over 7 million registered users. Various brands have hosted events, sold products, and tested designs and marketing strategies within Second Life to engage customers. Examples include Sun Microsystems holding a press conference, American Apparel launching a virtual store, and Lego hosting robot-building events. Educational institutions like Dartmouth College also have a presence in Second Life for activities like emergency response exercises.