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.
Redmine - Flexible project management web application
Dropbox - Online Sync and File Sharing
Basecamp - A simple and elegant project management system.
Google Drive - Access and sync your files anywhere
Asana - Asana project management is an effort to re-imagine how we work together, through modern productivity software. Fast and versatile, Asana helps individuals and groups get more done.
Mega - Secure File Storage and collaboration