Open source is making its way into more and more enterprises with cheap, robust alternatives to solutions offered by proprietary software vendors. Read this article to learn about nine open source companies worth watching in the areas of Web search, server virtualization, data integration, collaboration software and e-mail.

Read up on what became of last year's open source companies to watch.

Company name: Apatar

Founded: February 2007

Location: Chicopee, Mass.

What does the company offer? Tools that let customers integrate information from in-house applications or data sources with those hosted on the Web.

Why is it worth watching? Apatar makes it easier to form partnerships by more effectively sharing data across applications, says Nucleus Research Vice President Rebecca Wetteman. “With the proliferation of on-demand applications, there is a lot of valuable data — and potential partnerships — out there on the Web,” she says. “But it’s hard to form partnerships, because data integration between the enterprise and Web-based applications is difficult. Apatar bridges this gap by [eliminating duplicate data], filtering, naming and storing Web-based data.”

How did the company get its start? CEO Renat Khasanshyn previously headed Altoros Systems, which ran projects for customers who needed integration between databases and applications but could not afford expensive data-integration tools from vendors like IBM and Informatica. Altoros’ work was done manually and was thus error-prone and ineffective in the long run, Khasanshyn says. He became convinced that cost-conscious businesses would use an open source data-integration solution based on software tools rather than manual coding.

How did the company get its name? By Khasanshyn’s own admission, the name was inspired by “boring marketing research.” “About five short names, with six characters or less, which start with ‘A’, [are] easy to remember and have a .com, [or] .org domains available were offered for voting to about 20 people,” he says.

“They were asked to select the most attractive and easy to remember name. Although Apatar was not the leader most of the time, it demonstrated consistent results [second or third choice] in more than 70% of the votes.”

CEO and background: Khasanshyn, who immigrated to the United States in 2001, was vice president of engineering at PriMed, a discount insurance company in Tampa, Fla., and CEO of Altoros Systems, a distributed product life-cycle management company.

Funding: $500,000 from Altoros, Khasanshyn and co-founder Andrei Yurkevich.

Who’s using the product? 250 users, including Autodesk, Kenya.com and R.R. Donnelley.