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
PlanITpoker - PlanITpoker is a cool on-line planning poker app that helps Agile project teams estimate projects easily.
Google Drive - Access and sync your files anywhere
Firepoker - Agile Planning Poker powered by Firebase and AngularJS
Mega - Secure File Storage and collaboration
Planning Poker - Open source implementation of planning poker game (collaborative online estimation/voting tool).