Zimbra customers appalled at the company's planned acquisition by Yahoo are speaking out, saying they are vexed by the deal and upset over its possible negative consequences.

Skeptical about Yahoo's capacity to serve enterprise customers and suspicious about Yahoo's plans for the Zimbra collaboration and messaging suite, these IT professionals express pessimism about the deal announced Monday and expected to close next month.

A collective feeling of alarm and dismay emanates from a discussion forum thread which Zimbra created to obtain feedback from its customers. Already 9 pages long, the thread contains mostly negative impressions.

Zimbra organized a conference call this week open to all customers so that the company's top executives could answer questions and address concerns.

Neither that call, held Tuesday, nor reassuring messages from Zimbra employees in the forum have calmed customers.

"There is a lot of fear, uncertainty and doubt regarding Zimbra at the moment and it's not unwarranted," said Matthew Day, IT Manager at Langs Building Supplies in Brisbane, Queensland.

Just over a year ago, Day began researching collaboration suites for Langs and chose Zimbra Collaboration Suite over Microsoft's Exchange and Xandos' Scalix. Currently, 400 Langs employees use Zimbra's suite.

However, his misgivings about the Yahoo deal prompted him to scratch plans to renew Langs' Zimbra contract for 3 years, opting instead for a 1-year agreement.

Day has too many questions that Zimbra and Yahoo haven't answered to his satisfaction. Chief among them: Does Yahoo, whose online services are heavily focused on consumers, understand the needs of business customers?

"As an IT Manager, I would not have expected to ever see a Yahoo product in one of my production environments," he said. "I am concerned about how the culture of Yahoo will deal with the requirements of commercial users and the support they expect."

Day also worries that Yahoo's influence may negatively affect future development of the Zimbra suite, a concern shared by Dan Phillips, IT Manager at Other World Computing.

"Before the acquisition, Zimbra had only one purpose: to make a better product. Zimbra now has a different purpose and that is to ensure Yahoo's agendas are fulfilled," Phillips said.

Among his first tasks after getting hired 6 months ago was picking a new messaging platform for Other World. The Zimbra rollout was completed barely three weeks ago. He picked the Open Source Edition of the suite, which also comes in a commercial option called Network Edition.

The news of the Yahoo deal left him aghast. "I am certain I was not the only IT decision maker that felt disgust and despair after reading about Yahoo's [planned] acquisition of Zimbra," Phillips said.

Also deeply pessimistic is Dominic Ijichi, a Belfast-based Unix supercomputer administrator for a large bank, who in his spare time manages the Zimbra suite for a small finance company whose chairman is a friend of his. He predicts Yahoo will disassemble the suite and plug its pieces into Yahoo Mail. "I believe [Zimbra's suite] will be killed off as a separate product," he said.

Jim Hutchinson, IT Manager at Richmond Systems, in Washington, is scratching his head over Yahoo's motivation.

"What are they going to get for their US$350 million?," he said. "I can't see how Zimbra fits into the way Yahoo makes money."

In addition to downloadable, server-based versions of the suite meant to be installed in customers' premises, it is also available as software-as-a-service (SAAS) from third-party hosting providers. Keepnet, a U.K. provider of hosted IT services, recently developed a new Zimbra-based hosted service, but the company isn't feeling too hot about it now, said director Kevin Dontenville.

"We are disappointed that this acquisition throws many of the knowns out of the window. We need to decide whether to continue and risk losses which are significant to us or to change direction ... and find a new route forward for our new business," he said.