MyePets: So cute it's sickening

Tween marketing has undergone a bit of a golden age online in 2007, thanks to sites like Club Penguin and Webkinz which rely heavily on interactivity to keep kids coming back.

According to Advertising Age, interactive tween sites are now taking a page out of the Webkinz handbook, whereby kids purchase an offline item to either join or enhance the online experience.

To proliferate its virtual world, Webkinz relied on word-of-mouth to get youngsters buying stuffed animals that came with codes that "activated" a virtual pet online.

Mattel's Barbie Girls site will soon offer 5.5 million users the option of buying an MP3-player/flash drive that unlocks additional features on the site, where girls spend an average of 30 minutes a session.

Meanwhile, MGA Entertainment introduced Be-Bratz, a line of dolls "sold with a pet pink mouse and flash drive" that hooks users up to a virtual world online.

MyePets.com, another MGA project, has a business model slightly closer in type to Webkinz, where kids "rescue" homeless pets from the store (a la Pound Puppies, a series of despondent stuffed animals from the '80s) in exchange for access to the site.

Though it may seem the market for tween-focused virtual worlds is getting overcrowded, interactive sites now largely come stock alongside major toy launches.