LinkedIn is a professional social media platform with over 400 million members and 4 million active company profiles. The document discusses how LinkedIn can help companies build, engage, and recruit talent. It recommends a three step process: 1) grow followers by sharing relevant content tailored to different audiences, 2) engage followers by encouraging likes and shares, and 3) recruit by promoting jobs and sourcing talent proactively. Metrics like followers, meetings, candidates, and roles can then measure the ROI of a company's LinkedIn strategy.