Please Sirs of Zimbra/Yahoo!: Take into consideration releasing Zimbra (at least the "Community/Open Source Edition") under the GPLv3 in order to avoid Microsoft (or any other hostile attacker now or in the future) to close the code and bury the project. Zimbra is Nš 1 alternative to MSFT's Exchange and releasing it under the GPLv3 would guarantee a continuity of the current community of users, developers and contributors, fostering an environment where it can develop beyond the fear of proprietarization, oblivion or patent-related attacks.
Please do consider this very interesting discussion about the future of this wonderful project here:
Groklaw - What Will Happen to Zimbra?