“Second Life is about getting the better clothes and the bigger build and the reputation as a better builder,” said Julian Dibbell, author of “Play Money,” which chronicles his year of trying to make a living by trading virtual goods in online games. “The basic activity is still the keeping up with the Joneses, or getting ahead of the Joneses, rat race game.”

TO have a Second Life, one needs a computer, the Second Life software, and a high-speed Internet connection. You use a credit card to buy Lindens, and Lindens earned during the game can be converted back into dollars via online currency exchanges. Players start by choosing one of the standard characters, called an avatar, and can roam the world by flying or “teleporting” (click and go). Nobody can go hungry, there is no actual need for warmer clothes or shelter, and there is much to do without buying Lindens.

But walking around in a standard avatar, when there are so many ways to buy a better appearance, is like showing up for the first day of school dressed differently than all the other kids. You stick out as different, as an SL “newbie.”

“It’s hard not to fall into that,” Mr. Yee said. “There are shops everywhere, so it’s easy to say, ‘Oh, O.K., I guess I’ll get a better pair of jeans.’ ”

Second Life was started in 2003 by a Silicon Valley techie inspired by a sci-fi novel, “Snow Crash.” It is owned by a private company called Linden Lab. The original idea of the game was to unleash creativity. Residents don’t have to wear the latest fashions; they don’t have to look — or act — human at all. They can take any animal, robotic, or inanimate form they want.

And while there is a minority population of animal characters, and wearing butterfly wings is currently in vogue for humans, for the most part the population is young women bursting from their blouses and young men bulging with muscle. (Underneath the clothes are cyber genitalia, sold separately. Mark Wallace, a blogger who writes about Second Life, explained that the parts are not fashion accessories but rather “a functional appliance” for, ahem, entertainment purposes.)

While a frequent criticism of Second Life is that spaces are often empty and that there’s “nothing to do,” a crowd can be found at the mall, just as it can in suburbia. For example, the Xcite! store, which sells body parts, is “always crawling with avatars,” said Mr. Wallace, co-author of a forthcoming book, “The Second Life Herald.” Fashion is big business in Second Life, along with entertainment and land development.