Intuit has a unique “Narrowcasting" approach to its QuickBooks Live Customer Community.  It invites its "Diehard" users to support other users.  Note particularly:

“Intuit chose this "narrowcast" approach after Chief Executive Brad Smith heard what was going on at the Web site of Intuit's popular TurboTax product. Customers were not only asking technical questions, they were often outshining Intuit's own tech support staff by answering 40% of the queries themselves.

Since the latest edition of QuickBooks went on sale last October, traffic on its channel has tripled. At any time, 70% of customer service questions are answered by other QuickBooks owners, says Scott K. Wilder, who oversees the social network. Michelle L. Long of Lee's Summit, Mo., is often on the site. The 45-year-old accountant has posted more than 5,600 answers.

The social aspect of the program seems to have helped sales. The Mountain View (Calif.) company has sold 1 million units of QuickBooks at $200 apiece, boosting the software's market share by 4 points, to 94%.”