What's more, according to a study released this week by Forrester Research, if companies don't relinquish control of an online community to its members, they risk brand backlash, which could result in online bad-mouthing of their products or services.

There are several drivers for companies to launch and maintain online communities.

Some companies, like pharmaceutical giant GlaxoSmithKline, use communities as standing focus groups, the report noted. Others, like Hitachi Data Systems, are using them to provide customer support.

Intel, meanwhile, is using an online community model to gather feedback for use in next-generation chip development projects, and online brokerage firm TradeKing is using the technology to engage clients, an effort that has already bolstered its revenue.

But Forrester analyst and report author Jeremiah Owyang noted that not all companies have been able to successfully overcome the philosophical differences between traditional and online community marketing.

"Many companies have a hard time being successful with their community if they want to control it too tight," he noted. "The most successful companies let go of the control and acted more like a host, rather than a policeman. Second, many companies had a hard time kick-starting a community - just because you build it, it doesn't mean they'll come."

The most difficult part of setting up an online community, Owyang said, is attracting members and getting them to participate on an ongoing basis. Instead of bombarding a community with marketing messages, companies should instead "think more like a host at a party, one who is ready to listen and help," the report noted. "The key component to launching a successful community is putting members first," Owyang noted in the report.

To identify the major "influencers," or the most enthusiastic and prominent customers, companies can monitor blogs or search for loyal users in Google, the report suggested. Companies can offer these companies charter membership in a community.

To create online "evangelists," companies need to create ways to empower or reward community members. For example, one company interviewed by Forrester created a private "embassy" for the 40 most active and influential members. These members are cordoned off from the rest of community and given exclusive information about products and asked to provide feedback for new product development efforts.

Owyang also urged companies to let early adopters take ownership of the community. Reuters AdvicePoint, a community for financial advisers, used a direct-marketing campaign to invite investors to "claim their profile" in the community to create a sense of ownership and urgency, the report noted.

Companies also need to engage with the community and have mechanisms in place to monitor the community for flare-ups over bad customer service or product defects, Forrester said.

For managers of online communities focused on beefing up customer support, "the trick is to know when product teams should help customers and when they should just listen," according to the report. "In most cases, the collective consciousness of your customer base knows more about the products than the product team, so employees should spend a great deal of time listening."

And when customers aren't getting a question answered, product teams can step in, the report suggested.