For hosting common files it's ok. Also it is on Android too do, great to transfer files between your Windows and your phone. But if you want better security you have to subscribe a monthly offer.
Dropbox - Online Sync and File Sharing
Padlet - Visual boards for organizing anything.
Google Drive - Access and sync your files anywhere
Quizalize - Quizalize is a leading web-based and mobile-based classroom application that delivers the best and easiest way to differentiates your teaching.
Mega - Secure File Storage and collaboration
Popplet - Popplet is the simplest application to capture and organize your idea.