Ubiquitous Presenter (UP) is an outgrowth of University of Washington's Classroom Presenter (CP), a program that uses Tablet PC ink to allow instructors to annotate pre-prepared slides and students to create submissions for in-class activities. UP extends this functionality by taking many of CP's features onto the web.
UP offers the structure and detail of pre-prepared slides along with the flexibility of on-the-fly inking, leaving you free to pursue tangents, correct mistakes, and provide step-by-step in-class examples. Slide minimization and whiteboard features provide you with any extra space you need. Students can synchronize with your presentation via a web browser and watch it real-time, or remain unsynchronized and move between the slides at their leisure. All of your progressive inking is saved on the web, so students can return later and step through the lecture.
Additionally, UP provides a framework within which you can interact with your students. UP supports active learning through web submissions; students can type, draw, or write answers to sample problems or surveys.