You already know The VAR Guy spent last weekend researching open source desktop suites (see his Jan. 23 blog entry). Now, he’s back taking a look at the open source email market. Are VARs really seeing demand for open source groupware and collaboration software? Apparently yes.

Open-Xchange Server is quietly building a following among VARs that serve small and midsize organizations. During 2005, Open-Xchange was mostly sold direct. But by the end of 2006, roughly 80 VARs had completed multiple Open-Xchange deployments, according to Paul Sterne, CFO and General Manager of the Americas.

Admittedly, we’re not talking about massive Exchange Server or Lotus Notes migrations here. But The VAR Guy continues to see growing demand for open source applications that require minimal hardware resources, install quickly and don’t have Windows’ security holes. Eager Open-Xchange adopters include small and midsize government organizations, schools and universities. The typical deployment involves 100 to 1,000 users, but some Open-Xchange sites have nearly 10,000 inboxes.

While Open-Xchange is available in multiple countries, the company is working to develop a specialized version that targets the US market. The reasoning for this is quite simple: European organizations are comfortable buying modular, customized offerings; in contrast, the US version will deliver more of a plug-and-play, standardized release, Sterne says. Current Open-Xchange VARs are extremely technically proficient in Linux, but the forthcoming US edition will likely appeal to Windows Server and Exchange Server veterans, The VAR Guy suspects.

Also this year, Open-Xchange will work more closely with SpikeSource–which is helping to certify interoperability between open source applications. Translation: Watch for Open-Xchange to integrate more easily with MySQL, SugarCRM and other open source apps that are gaining critical mass.