It's incredibly vast, lots of fun to be in and very, very addictive. Second Life is a 3-D virtual world that's entirely built and owned by its residents.
Since going live in 2003, Second Life has been enormously popular and the developers Linden Labs claim that over 5 million people worldwide now happily call it home. To get started with Second Life, you have to sign-up for an account which is quick and simple.
You have to choose a first and last name (which in the end, I had to select from a pre-defined list as it wouldn't accept my suggestion for some reason) and what you'd like your Avatar to look like. Confirm your e-mail and you're ready to go. The great thing is Second Life is that it is free to use which means you can basically wander about and chat to people as much as you want. However, after signing up, you are offered the chance to upgrade to the Premium version which gives you your own 3D house, Virtual Currency to spend and access to adult 18+ areas as long as you are over 18, of course. From the moment you enter the World, you'll be overwhelmed by the sheer number of possibilities and worlds on offer. To get you started, there's a mini 6-step course which allows you to master the basics like walking, sitting and yes, flying. You also learn to chat to people via a simple IM chat client although some worlds also support voice chats. I heartily recommend the Quick Start guide though which opens in your browser to help you get to grips with the game more easily than walking around randomly is doing it the hard way.
The sheer size of Second Life is amazing. You're surrounded by not only thousands of virtual worlds but also people eager to shat to you. You can teleport yourself to a new world simply by clicking on it on a map. The unique thing is, because residents retain the legal rights to their digital creations, they can buy, sell and trade with other residents although this is only possible in the Premium version. The developers claim the Marketplace currently supports millions of US dollars in monthly transactions which is handled with the in-world unit-of-trade, the Linden dollar, which can be converted to US dollars at several online Linden Dollar exchanges.
Although some users complain that Second Life can be sluggish, I had absolutely no problems. However, it does require some serious hardware and the developers recommend at least 1GB of RAM and a high-end processor for best results. However, it did log me off automatically saying that "demand was particularly strong in my area" so be aware that the servers may not be stable. Second Life is an amazing accomplishment. If you're willing to invest the time needed to master the basics, you'll soon get sucked into Second Life's virtual world of unending possibilities.