This document discusses different options for sharing presentations online, including Slideshare, Google Docs, and Prezi. It then introduces CoCoMa, a web-based collaborative platform for creating and editing presentations. CoCoMa allows lecturers to author presentations while students can create their own versions, with the lecturer maintaining authority. Benefits include alternative explanations, solving open questions, and optimizing presentations for individual preferences. CoCoMa uses standards and is accessible through a web browser.