Slideshare.net is a website for sharing presentations, documents, and PDFs that has over 25 million monthly visitors. It was started in 2006 by founders with experience at MindCanvas, CommerceOne, and PepsiCo, and is advised by Guy Kawasaki. Users can upload files up to 100MB for free, with options to make presentations private or allow downloading. Slideshare integrates with tools like Google Docs and has plugins for Firefox and Office 2007.