One of the biggest votes of confidence in open source can be found in the number of previously closed-source companies adopting it as part of their strategy. Here's another:
In an effort to sponsor and support the creation of an enterprise open source exchange replacement, the company will contribute the full core of the server-side source code of the Zarafa platform – known for its 100% MAPI compatibility and flexibility – to the community. This will allow more options for compatibility, localization, enhancements and further integration options with other systems.
Zarafa open source offering will consist of the Zarafa server, Z-Merge (a new web services API platform for application integration), the Zarafa IMAP/POP3/iCal gateway, the Zarafa Administration Console, the Zarafa WebAccess and many other tools and services. It is the only groupware platform that includes open source ActiveSync compatibility, which enables organizations to have remote synchronisation and pushmail for Windows Mobile, Nokia’s Mail for Exchange and iPhones.
Obviously, a purely open source drop-in replacement for Exchange would be pretty handy for enterprises, so Zarafa's move is welcome. And in case you were wondering:
Zarafa is the Arabic word for giraffe. Like a giraffe, Zarafa has the overview in the landscape of other applications to collaborate together in an open and friendly way.