Contrary to what seems to be a common 'this is bad' vibe going through this thread.
Our team think this is fantastic and look forward to seeing what this new partnership brings to the Zimbra product. We proudly announced this to all the Zimbra customers we currently support.
And to those that believe Yahoo! does not 'contribute much' to the open source community - please remember that Yahoo currently employees Rasmus Lerdorf, creator of PHP. And much of Yahoo Mail runs on PHP. Listen to
The TWiT Netcast Network with Leo Laporte
Congrats Zimbra! And welcome Yahoo!