LinkedIn is a professional social network with over 120 million members. This network allows users to stay in touch with colleagues, employers and friends while establishing and controlling a professional profile. Unlike Facebook, which has a broad social reach, LinkedIn is a professionally-focused network. There are no check-ins at local bars, photos of children's friends, or walls to post comments. Instead, LinkedIn is dedicated to building business connections, making new contacts, job searching and recruitment, and finding expert ideas and answers. This guide will tell you what you need to know about the Internets most powerful business network, including how to land your dream job and even how to grow your small business.