LinkedIn is a social networking site for business professionals that allows users to stay connected, find job opportunities, and get business advice. While more formal than Facebook, LinkedIn is described as a "must-have" tool for small businesses. The document cautions that users should have clear goals for joining sites to avoid addiction and losing focus, and recommends finding balance when using social networks. It also raises questions about whether the market could become saturated with too many social networking options, and whether these sites may decline like other technologies or remain popular long-term.