The direction of which technology will be 'integrated' into the other is clear:
"Zimbra offers incredible technology. We see great opportunities to incorporate some of their best-of-breed features (I really like their calendaring) into Yahoo!’s industry-leading communications products."
Zimbra is so damn cool - Yodel Anecdotal
"into" Yahoo products.
Congratulations Zimbra Team.
Congratulations Yahoo for the good timing, and that you get more out of the deal than Zimbra. You gain not only the technology, but a competitor out of the business at the very best moment where the number of licensed users rised quickly and customers of Zimbra where getting bigger and bigger.