A basic but sturdy tenet of social media is to go where the people are. So if virtual worlds like Second Life have lost some cultural cache to the likes of Twitter, Foursquare, and Facebook what's the point of getting involved? In short, setting up your own avatar, or even an in-world space for your company can save you money and maybe even get that eyeball play your marketing team has been gunning for.

For starters, just because virtual worlds are no longer a media darling doesn't mean they emptied out overnight. "I think it's trending slowly but inexorably upward," says Michael Wilson CEO of Makena Technologies, which runs the virtual world There, when asked about the number of people using virtual worlds.

The head of the San Mateo, California-based company adds that trendier social media can be a boon rather than a bust for virtual worlds. "The problem with most virtual worlds is that they are islands. So we're currently working on a very deep integration with the major social media companies."

One way virtual worlds are being integrated into other social networks is through games such as FarmVille and Mafia Wars. "I think there are a lot of companies who are seeing the addictiveness and the success of those types of social media games and are looking at trying to get in on the action," says Clark Aldrich, a consultant on the virtual space and author of The Complete Guide to Simulations and Serious Games.

As the title of Aldrich's book suggests, not all "games" are light-hearted. He points to Tycoon Systems' serious game Industry Masters, which has integrated simulated worlds into social media in order to train business people and entrepreneurs to run a company or manage a team.

In Second Life, the most popular virtual world run by the San Francisco, California-based company Linden Lab, prototyping products and having virtual meetings or trade fairs are other popular applications for businesses. One active community is architects who can build mock-ups cheaply for clients without mixing a drop of cement.

Chris Collins, Linden Lab's general manager of enterprise, also mentions that accountants have a vibrant community in the space, using it for private meetings and industry conferences. "The in-world economy has grown this year while the rest of the world was on the decline," says Collins, "It's the world's largest virtual marketplace." With one million monthly users, projections suggest that $500 million will change hands in-world in 2010.

Still Wilson says that the hype of yesteryear "was about selling. Now it's more focused on brand awareness." As a business just starting out in a virtual world you should "start with something small and manageable and not very expensive and learn from that and then move on," Wilson says. "Don't come in and spend millions of dollars on an installation because, No. 1, if it doesn't work you're going to be sad, and No. 2, that doesn't give you a chance to incrementally learn anything."