LinkedIn SlideShare is a slide hosting service that allows users to upload presentations in various formats, serving both business sharing and entertainment purposes, with an average of 70 million unique visitors per month. To earn money from SlideShare, users should create engaging content, optimize their presentations, carefully select categories and tags, and promote their work effectively. Additionally, monetization can be achieved by building an email list and driving traffic to linked websites while actively promoting presentations across social media and other platforms.