Cryoserver - Cryoserver is an all-in-one email archiving solution that empowers you to preserve your email in a tamper-evident archive, making you transform your data into a useful archive for everyday use.
ShareFile - Secure file sharing and sync
Gmvault - Backup the emails in your Gmail account.
Google Drive - Access and sync your files anywhere
imapsync - Console-based utility for migrating IMAP mailboxes.
Dropbox - Online Sync and File Sharing