Not sure it is strictly a Web2 tool but OfficeMix offers some very interesting and impressive features for creating interactive presentation and guides through PowerPoint.
Huge range of opportunities for sharing resources via cloud or Office365 video and institution. Embedding also possible
I particularly like the range of interactive quiz features that you can insert in addition to the video screen capture feature which instantly adds video to a slide.
Lots of potential for creating engaging tutorials and resources that work equally effectively on tablet as on PC.
An added bonus, found by accident was the Office Labs. Very pleasing to see Office make greater strides in the education sector. Current sitting in the labs are a range of Phet Science simulations from Boulder University, Geogebra for PowerPoint, Fluid Maths, Online Python tutor and a Web Viewer which allows you to insert a web page on your presentation.
Sourced through Scoop.it from: mix.office.com