Even preteens have social networks now. When my son was preteen he used to spend time on Habbo Hotel, a 3D chat environment.

Sites like club penguin, Whyville.net, Habbo Hotel, Imbee.com and Nickelodeon's Nicktropolis offer tweens a MySpace of their own. The sites offer either fantasy worlds (members at Club Penguin have tuxedoed birds as avatars) or more standard fare like blogging and music sharing. Club Penguin had four million unique visitors in January 2007, according to comScore Media Metrix. Via eMarketer

The important take away from this trend is that kids are your future consumers and are very social and well networked. They will be expecting to network and work online. They will redefine your market and the workplace.