A neat new BrandWeek article talks about major brands' efforts to move into the online social networking and virtual worlds space, and why some have succeeded -- along with why others have failed. It mentions appeal for niche audiences and perks for invested members -- using BarbieGirls as an example, with content that becomes accessible with the purchase of the BarbieGirls' MP3 player. From the article:

With brands ranging from cars to tequila to retail setting up community hubs, The Coke Show joins a growing list of cautionary tales, including Wal-Mart's ill-fated social network The Hub and Anheuser-Busch's Bud.tv, showing it is far from easy to tap the same kind of sharing vibe that's fueled the rise of MySpace, YouTube and Facebook.

Those that have succeeded either tap into the existing passionate audience of a niche brand or offer some functionality that cannot be found already on popular social media sites.

"There's been a me-tooism on the social-networking front of 'I need to create a MySpace of my brand,'" said Pete Blackshaw, CMO at Nielsen BuzzMetrics. "Every brand needs to do some element of it, but do they need to go all out? It's not clear."