While everybody seems to be talking about Second Life just at the moment, it's worth remembering that virtual worlds have been around for quite some time.
Originally they were text-based virtual meeting spaces but about ten years ago they turned 3D with the arrival of online environments such as ActiveWorlds and EduVerse. I suspect these resources appealed only to patient users as basic dial-up connectivity made navigating around and communicating painfully slow.
However, as faster internet services became more common, multimedia services appeared, such as Mobilesdisco and the more sophisticated Habbo Hotel. These environments quickly became popular with teenagers naturally au fait with computers.
But now those teens have now entered their 20s and have helped, along with the ubiquity of broadband, to drive the popularity of the latest online worlds such as Second Life.
So where are these virtual world likely to take us next? Well, I expect us to see the emergence of artificial intelligence 'bots.
Virtual worlds make it easy for us to switch our identities so that when we slip into our virtual skins, we may not know which friends are real and which are fake.
And so when our 'bots develop some intelligence, they can act on our behalf, retrieving information and interacting with others. This may be an appealing way of interacting with the more tedious members of our social circle and perhaps even relatives, but other 'people' may also be bots, powered, preened and postured by computers....
It is also probable that our future virtual worlds will be more integrated with our real environments and they will also be mobile. Some buildings may offer virtual versions of worlds, but using actual physical rooms to set them in. Rather than view them on screen we could use glasses, or even active contact lenses, to enhance our immersion and aid mobility.
In fact, we could then easily switch between viewing the real world, the virtual world, or a mix. So, for example, you may be walking along the street, where you get a call from someone in a virtual world, and instead of talking on your mobile phone, you instantaneously switch into the mixed reality environment.
As these worlds become more familiar and sophisticated, we are likely to use them as communication spaces for work as well as play, perhaps to collaborate with remote workers or encourage new kinds of creativity. They will become as standard a communication tool as a mobile phone.