Founder and CEO, Linden LabsRank: 25Why he matters: Virtual worlds, like real nations, are starting to generate significant economic activity, and Rosedale's Second Life is the most formidable virtual world of all. Not only is it home to nearly 2 million active "residents," but it has spawned an online economy where more than $1.5 million worth of digital goods and services are traded every day.
Second Life is no longer just a game; it may also be the precursor of a more visual, three-dimensional Internet. Instead of looking at a flat e-commerce webpage, imagine dropping by a 3-D virtual store. Sound far-fetched? In Second Life, it's already routine.
Meet 50 Who Matter winner Gina Bianchini. Her site, Ning, lets anyone be a social networking mogul. (more) 
