Dropbox - Online Sync and File Sharing
Sync.com - Sync. com offers a backup tool and a file sharing service, rolled into one.
Google Drive - Access and sync your files anywhere
CloudBerry Box - CloudBerry Box provides bi-directional synchronization of data across remote computers.
ownCloud - ownCloud is an open source project enabling businesses to host their own cloud storage while maintaining regulatory and compliance needs.
Yandex.Disk - Files on Yandex.Disk won't get lost if your phone or computer breaks.