At the recent Virtual Worlds Conference held in New York, a keynote speaker asked the crowd of a few hundred for a show of hands. About a third of the attendees represented kids' brands, a third were with virtual world companies and a third were vendors of software and other technology.

Only one person identified herself as a brand manager.

Why don't more brand managers market in virtual worlds?

For one thing, they're scared of wasting money. Established brands spent millions building virtual stores, only to reap disappointing sales, or worse, to be outsold by the brands of in-world entrepreneurs.

Robin Harper, senior vice president of Second Life parent Linden Lab, told eMarketer that part of the problem was a "Build It and They Will Come" mentality.

"Like any other campaign, you have to consider what your objectives are," said Ms. Harper. "Building a virtual store and then not staffing it properly will leave customers disappointed."

Ms. Harper said that on the positive side, there are a lot more ways to market in a virtual world than just setting up shop. She said that Toyota's Scion campaign let Second Lifers test drive in-world versions of the vehicle, making for a more engaging experience than items which couldn't actually be used in the virtual world.

The word "engagement" came up repeatedly during the Virtual Worlds Conference.

That's partially a reaction to a lack of established marketing metrics for virtual worlds. There is also a lack of faith in some of the data that's been thrown around. Craig Sherman, CEO of Gaia Online, said during a session on virtual goods that virtual worlds don't do themselves any favors when they inflate their numbers.

"If 46 million people have visited your site, but only two million do so regularly, then you have two million users—not 46 million," said Mr. Sherman. "And that's fine."

During the same session, Millions of Us CEO Ruben Steiger said that real metrics and benchmarks for success were difficult but not impossible to track.

"Data is trackable on where users are, what in-world items they have and the like," Mr. Steiger said. He added that although many metrics were not comparable from world to world (e.g., Second Life user data and There.com user data might not be completely apples-to-apples), basic statistics like number of users and time spent using a branded item were always useful.

Ben Richardson, vice president of business development for virtual world There.com parent Makena Technologies, told eMarketer that rather than attempt to gain brand recognition within an established community, marketers could also create their own virtual worlds.

There.com recently white-labeled a virtual Ford Model contest for MTV, sponsored by Mariah Carey's perfume. The contest drew 750,000 visitors within two months. Modeling agency staff went in-world, giving fashion advice to visiting avatars.

"What works depends on the community," said Mr. Richardson.

However, Millions of Us' Mr. Steiger said that brands that attempted to create permanent alternatives to established worlds like Second Life would be wasting time and money.

Still, virtual worlds will continue to attract marketers as consumer media consumption changes—especially among young users.

David Simmons at Entropia parent Mindark said "the amount of time that people spend online in virtual worlds demands attention."

Tomorrow's adult consumers are forming their media habits today. Learn more by reading eMarketer's Kids and Teens: Virtual Worlds Open New Universe report.