Of the many business social networking sites that populate cyberspace, LinkedIn is by far the most often used by professionals across industries. It's a little bit like MySpace for grown-ups--a place where you can post your resumé, bio, likes and dislikes, all in the context of your professional goals. Its benefits, if used effectively, are manifold: It offers the ability to find qualified job candidates, network efficiently, find the perfect job, form a strategic business partnership, get a client, pitch the media or even make a sale.