LinkedIn is a social media platform for professional networking. It allows users to create personal and organization profiles to connect with colleagues and donors. The document provides tips for non-profits to set up and utilize LinkedIn, including claiming an organization's page, building a professional profile, following the organization, and sharing content to expand reach. Best practices include establishing an expertise brand through a complete profile, driving support through volunteer and cause sections, expanding networks through connections, collaborating through groups, and staying top of mind by sharing regular updates.