Left Behind Games (fka LFBG)

[The Rainmaker]

•Vertical social networks. Social networks that cater to the specialized interests of their members offer a premium of eyeballs and opportunity for advertisers, who want a safe, well-lit place they know and trust.

"If you have the right audience and the right engagement, you can build a real media business," says Tina Sharkey, CEO of BabyCenter.

For most social networks, the goal is to carve out a niche where they fit in a market dominated by generalists MySpace, Facebook and Bebo, says Aaron Levie, CEO of Box.net, an online file system.