This week, the company released a Web application called Little Black Book for Facebook members.

FORBES: Seeking Love Around The Web

But the people at Samsung were ready and the little black boxes, no bigger than a book, were already on display.

CNN: Tech companies go into battle at CeBIT

And in the center is LinkedIn's richest and fastest-growing opportunity: turning the company's 161 million member profiles into the 21st-century version of a "little black book" that no corporate recruiter can live without.

FORBES: Feature