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
Smoke Free - Virtual "Quit Smoking Buddy" in your pocket
Google Drive - Access and sync your files anywhere
Quit Genius - Quit smoking with personalised and proven therapy 🚭
Mega - Secure File Storage and collaboration
Quittr - A cigarette case that helps you quit smoking