"On the internet, nobody knows you're a dog," says one pooch to another in front of a computer screen in the famous 1993 New Yorker cartoon. In the online worlds of World of Warcraft and Second Life, you can be a dog, elf or an orc, and nobody knows you're a human.
But the desire to don a virtual disguise may now be waning. In some of the newest virtual worlds, people are happier being themselves.
Avatars are accurate representations of their owners and a right-click of the mouse over their characters can reveal their real name, age and interests. Video games have historically been the main influence for virtual worlds but the new trend for real-life representation is being driven by social networking.
Corey Bridges, executive producer at Multiverse, a creator of online world software, says the next "killer application" that will spread the adoption of virtual worlds into the mainstream is one that allows their integration with social networks. "There's this notion of people wanting to run around in Second Life with a goofy name but a lot of people will want to experience the virtual worlds as themselves.
"They are building representations of themselves on MySpace - their page is, in a sense, their avatar. Doing that in a 3D space can lead to more interaction between these social mavens and they will want to integrate it tightly with their social networking profile."
The video game industry still dominates online role-playing games, emphasising fantasy elements and beautiful 3D graphics, but it is internet companies that are beginning to offer these alternate universes. They may not look as good but they can work in a web browser and provide connections between different worlds.
Multiverse was founded by ex-Netscape employees - the people who popularised the graphical web browser. Kaneva, a virtual world that launched this year, is the brainchild of Chris Klaus, who developed it after he sold his internet security company to IBM.
"We're taking a unique spin in integrating a lot of internet technologies such as social networking and live streaming of video from services like YouTube, so it's not a closed system but a very open system," he says. The focus is on entertainment. Members watch films, listen to music, play games and dance in virtual clubs together rather than build characters and homes.
"The majority of us don't have time to create. We'd rather consume. We wanted to enable a fun, entertaining social world to come and meet others and have real relationships." Kaneva encourages the use of real names and personal information to help people interact. He says virtual interaction is much more immediate than in real life. "It's much easier to read your profile in the virtual world and see you have the same friends and interests and, all of a sudden, you have those connections."
Venture capitalists are taking interest in virtual world start-ups. Nearly $200 million has been invested in 33 companies over the past 12 months, according to a study by Virtual Worlds Management.
Redpoint Ventures, the only institutional investor in MySpace, has invested in four companies, including Gaia Online. Scott Raney, a Redpoint partner, says the group had been impressed at how MySpace users were on its site for 45 minutes to an hour, but Gaia users spend more than an hour there on average. "We were thinking 'what's next?' when we sold MySpace to Fox."
He says they were aware that a shortcoming of social networks was that they "don't provide the online hangouts". Raney sees virtual worlds as the logical next step for social networks, which will have to adopt some of their features. "Facebook is looking at this: people are delivering casual games that allow you to interact and that's a step in the right direction." Fouad ElNaggar, another Redpoint partner, adds: "Some developers are looking at how to put a virtual room into a Facebook profile. They want to enable interaction that's more than posting something on somebody's wall."