With Habbo Hotel, the virtual world (VW) for teens, now boasting nearly 10 million unique users a month, it's clear that some VWs are making real money.
Disney was quick to spot the trend and snapped up Club Penguin, the VW for pre-teens, for £375 million. It, too, is doing well, as is the VW bellwether, World of Warcraft.
But what about VWs for grown-ups? Yes, we have Second Life, sometimes cruelly dubbed 'Get a Life', but the general feeling is that VWs are still too big, clunky and complex to break through to the adult mainstream, whether for leisure or business. Most people just don't have the time or the inclination to spend hours finessing their avatar's hair style.
This is why Google's entry into the 3D space with its 'Lively' in-browser VW-lite application is interesting. It signifies a general move towards thin-client 3D in-browser applications that don't need big download times. For the 3D web to take off it has to be instantly accessible.
But why 3D anyway, with all its extra development costs, rather than 2D? Its main appeal seems to be the ability to interact simultaneously with lots of people in a more visually appealing and intuitively understandable environment. Great for social networking sites, online galleries, expos, that sort of thing. Some developers confidently predict that the whole of the web will be 3D within five years. I think that's going a bit far, but it's definitely a space worth watching.
For a round-up of the latest VW developments read my New Media Age feature 'Get Real' .