Second Life is nothing if not an experiment. Second Life, developed by novice studio Linden Lab, is a massively multiplayer online game most akin on the surface to the upcoming The Sims Online. On the outside, Second Life is a fully 3D game where, as in The Sims, you control an in-game avatar, which you use to interact with the world. But the comparison really only provides a starting point to look at a game that is wholly different structurally.

You'll craft your own world and persona in Second Life.

Though Second Life is like an RPG in that you control a character, the goals and aims of the game are very different. Instead of having overarching goals or a predefined purpose, you are given free rein to do whatever you want in an expansive, modern, 3D world built largely by the players themselves. You start with a certain amount of money and a customizable house and are allowed to go anywhere you want from there. Some may choose to pursue social interaction. Others might prefer to trade items and goods. Still others might decide to create the very items that are traded and gawked at. Second Life aims to create a world where you can truly leave your mark.

One way Second Life accomplishes this individuality is by allowing a mind-numbing amount of character personalization. Each facet of your in-game avatar can be tweaked. For example, there are 30 sliders adjusting your character's hair in different ways, and each slider has 100 unique positions. There are six different sliders for shoes. On top of this, not only can a character's look be changed, but so can the character's body type and structure, and it can all be done on the fly. But perhaps what's most interesting is that you can upload your own textures for your character, which lets you truly and creatively add to the gameworld.

Central to Second Life's uniqueness is that the entire game is streamed off the Internet in real time; nearly nothing is stored locally on your machine. Opened with only an 8-megabyte executable, all game content--from the world and the architecture, to the character models, textures, and sounds--is streamed from the server to your computer as you play over a broadband connection. The servers themselves are arrayed in something like a peer-to-peer network most commonly used by programs and networks like Kazaa. The effect accomplished is similar: If you would like to contribute to the world, you can, because your unique content can be uploaded and shared with everyone.

Nothing--not even your house--is stored on your hard drive. Instead, the entire game is streamed off of the Net.

Possibly Second Life's biggest calling card is its built-in user-creation system. Instead of creating a game and letting fans modify it by creating mods like Counter-Strike or Day of Defeat, the developers of Second Life have created what is essentially an ever-evolving mod world. Almost nothing in the game will be set or defined, and instead you can manipulate and create, just as the mod-makers do, but now in the context of a game experience.

Linden Labs is betting on the innate lust of players to learn the tools to create complex content. The tools built into Second Life seem almost as powerful as the tools used by the fans that created mods like Counter-Strike, and they also seem just as complex. Using the built-in tools, you can construct items in-game by sculpting polygons and by carving and combining shapes just like professional mod-makers. When we saw Second Life, we watched as a player created a chain in-game by cutting and shaping polygons. Once items are shaped, you can apply scripts that control how the item acts and functions. Similarly, custom textures can be uploaded and applied to give the item a wholly unique look.