Not unlike stone tablets, used in classrooms since 1900BC, and similar slates used in classrooms until about 1930- anyway that's the comparison made here by Jordan Shapiro who reviews educational apps professionally: <a href="http://www.forbes.com/sites/jordanshapiro/2015/12/12/the-top-50-educational-apps-are-mostly-all-stuck-in-the-stone-age/">http://www.forbes.com/sites/jordanshapiro/2015/12/12/the-top-50-educational-apps-are-mostly-all-stuck-in-the-stone-age/</a> "Ancient students and teachers of Mesopotamia used clay tablets for the same reason (and in the same way) that we still use dry-erase boards: clay allowed pupils to write, wipe away mistakes, and then iterate. The digital tablet now works in very much the same way. It’s beholden to same essential metaphors. Tablet computing with apps always maintains that same spirit of impermanence and ephemerality. Nothing is stored locally, everything hovers in the cloud..." Perhaps more optimistically around our much-loved literacy apps: "The Joan Ganz Cooney Center report, Getting a Read on the App Stores: A Market Scan and Analysis of Children’s Literacy Apps, is full of tons more interesting discoveries, plus a few recommendations for app developers and the industry as a whole" <a href="http://www.joanganzcooneycenter.org/publication/getting-a-read-on-the-app-stores-a-market-scan-and-analysis-of-childrens-literacy-apps/">http://www.joanganzcooneycenter.org/publication/getting-a-read-on-the-app-stores-a-market-scan-and-analysis-of-childrens-literacy-apps/</a>