Several years after open source began to take the world by storm, the question of how to make money in the genre still remains an issue, with a prominent Novell official advising caution for those considering a move to open source.

The official, Novell Vice President Miguel de Icaza, actually heads up Novell's open source Mono project, which provides a version of the Microsoft .Net Framework for use on non-Windows platforms such as Linux.

"If your livelihood depends on the product that you're selling, until you can figure how you're going to make money on that thing, I say, keep it proprietary," de Icaza said.

There is no rush to go open source, he said. "In my experience, making a successful open source business has been incredibly difficult," de Icaza said.

He was among panelists and audience members who pondered the question of how to make money in open source in a session entitled, "Is Open Source Old News?" at the Microsoft PDC (Professional Developers Conference) in Los Angeles.

De Icaza's remarks were in response to an audience member, independent consultant Giovanni Bassi, who raised the question of making money via open source. His clients, he said, do not have anything to sell if they put their software into open source.

"I hear about selling support instead of selling software," Bassi said. But his clients "don't buy" this notion, he said.

Young developers without a lot of obligations can more easily consider doing open source projects, de Icaza said. But someone with a family and tuition to pay has to tread carefully when taking a technology to the open source route.

"You need to take those steps carefully in my opinion. And support, by the way, is a horrible business," said de Icaza, who added he would rather be writing code than taking support calls. Afterward, he did acknowledge services as an option for monetization of open source technology.

"I want to be writing code, and I want to be paid to write code," said de Icaza. Making money via open source is a "challenge," he said. But not every project will be able to be commercially sold, he added.

Open sourcing can work if a usage license is structured with limitations on commercial use, such as what MySQL did with its open source database. (MySQL  generated revenues by selling support subscriptions.) Open source also can be an option if it presents a technical advantage, such as what Google did with its GPS data, de Icaza said.

While Mono is open source like the related Novell Moonlight project, Novell last week introduced a commercial product, Mono Tools for Visual Studio, which leverages Mono.

Also during the panel session, Sara Ford, program manager for Microsoft's site for open source projects, noted she had a learning curve regarding open source as a Microsoft employee.