OwnDrive is easy to use free online storage service for businesses, professionals, and individuals to store, backup, collaborate and share files with others.

Kopano is an open-source groupware application suite originally based on Zarafa.

Baïkal is a Cal and CardDAV server, based on sabre/dav, that includes an administrative interface for easy management.

Memotoo sync all your contacts from Gmail, Facebook, phone, Thunderbird, Outlook, etc in a single address book.