Second Life, and Maybe a Third or Fourth

Following the success of Second Life as a virtual destination for millions, many big name companies including Sony (SNE Quote) and Lego are trying their hand at establishing their own digital world, setting the table for a potentially fierce Internet competition.

Second Life, the massive multiplayer online world, allows users to log on through the Internet and create 3-D computer-generated identities. Businesses such as Cisco (CSCO Quote), Dell (DELL Quote) and IBM (IBM Quote) have already set up shop in Second Life, making it the first destination for real-world companies looking to extend their brand in to the virtual realm.

Linden Lab, the San Francisco-based creator and maintainer of Second Life, has big numbers. The virtual world's population is quickly approaching 5 million residents, more than tripling over the last six months. ...