Box - Box offers secure content management and collaboration for individuals, teams and businesses, enabling secure file sharing and access to your files online.
MailStore - MailStore Home - A 100% free single-private-user desktop solution
Nubo - A self-hosted file sharing application in Haskell.
MailSteward - MailSteward : The Ultimate E-mail Manager for Mac OS X
Filecamp - Digital Asset Management & Online Proofing tools beautifully integrated, into one secure and cost-effective solution. Manage all your digital marketing assets from your own good-looking, easy-to-use spot in the cloud. Unlimited users in all plans!
Gmvault - Backup the emails in your Gmail account.