Interesting rumor - but I agree with Chris Wolf and would add one possible scenario: Cisco, EMC, and VMware formed the Virtual Computing Environment (VCE) to help organizations with their private cloud implementation (per this Cisco release: Accelerate the Journey to Private Cloud Computing). I would expect that VMware would tailor Zimbra to work with Cisco's emerging collaboration platform and efforts to leverage WebEx and SaaS-based e-mail.
This line-of-thought is just one possible scenario that might rationalize the deal if VCE actually does bring Cisco, EMC and VMware closer together. Such coalition cooperation might result in other independent actions taken my coalition vendors to acquire and partner in seemingly random ways that synergize VCE overall.
For instance, it is highly likely that Cisco will need robust content management services down the road. If Cisco wants to avoid getting into the ECM space directly, I would expect Cisco to leverage its VCE partner EMC in that regard (via Documentum). If VCE is indeed strategic for these three vendors - then I imagine that the analyst community might want to correlate patterns with VCE in mind - if VCE becomes/remains a credible force re: private cloud implementations rather than a marketing conduit for participating vendors.
But some observers said the move makes a lot of sense, noting some natural synergies between VMware and Zimbra. Richard McAniff, VMware's newly installed chief development officer and executive vice president, was a longtime Microsoft executive responsible for Microsoft Office. And VMware CEO Paul Maritz, also a Microsoft veteran, showed his propensity for moving up the software stack with the acquisition of SpringSource last summer.
Beyond these synergies, acquiring Zimbra -- or a company like it -- is a crucial move for VMware's continued survival, argued Chris Wolf, an analyst at Burton Group. On the Twitter site, he wrote that VMware's business can't always be about running Microsoft applications in virtual machines, and that if VMware can break organizations' dependency on Exchange, they may loosen their dependency on Microsoft.
If the VMware-Zimbra acquisition goes through, VMware has plenty of legroom to take on the burden of hosting a large-scale email service, thanks to its enormous data center in Wenatchee, Wash. that was completed this fall.