A possible answer to the infamous question, "What is SecondLife?":

2nd life is like The Matrix. It's a reflection of real life, but without the limitations of real life. You can defy gravity and create things at will. In addition, you can utilize the advatage of a computerized world. For example, one person creted a "universal translator" on it. You set it to the language you want to traslate to, and everything that is said to you in that language is sent to Altavista's BabelFish site, run through the translator into your language, and appears on your screen in the game within seconds in your language, and everything you say is automatically translated to the other language, too. You can hold a concert for friends across the world by streaming in audio. Anyone in the world can come just by sitting down to a computer and turning on 2nd Life. These are just a VERY small peak into what 2nd Life can do. Professors are actually holding college courses in 2nd Life, utilizing the fact that anyone from anywhere can get to it, and using the ability to manipulate the in-world to help illustrate their points.

Need a purpose? A "gaming" aspect to your online time? Users have created their own games in-world that you can go to and do, too. And that's the thing. Users create them, they don't need a corporation to support them, so new and inventive ideas are everywhere. Any creative outlet you can think of is all housed in one world, faciliated by the tools that Second Life provides, and the fact that anyone can come to what you put up, instantly, from anywhere in the real world, just by sitting down to a computer.

Source: an anonymous reply to a story that appeared on Slashdot on October 15, 2006.