Apple Keynote (computer or tablet) has been upgraded to allow a slide deck to be shareable. This requires that the file is saved in iCloud. The controls (available under the share menubar option) allows the filed to be shared in several ways and to allow read only or modify options. I would think there would be many classroom opportunities based on these capabilities. 

https://www.icloud.com/keynote/0fgyPDnKJ3X91dzKeR9PZeoyA#Petrified_Forest