You can try to avoid open source, but it's probably easier to get out of the IT business altogether. By 2011, at least 80% of commercial software will contain significant amounts of open source code, according to Gartner.

"To some of you, this is shocking, you don't believe this," Gartner research vice president Mark Driver said this week during the keynote session of Gartner's Open Source Summit in Las Vegas. "Others are saying, 'Forget 2011, it's already here today.'" Even if they don't plan to use software that's fully open source, network executives should pay attention to this trend because the open source choices commercial vendors make can expose users to risk or create competitive disadvantages. "Open source is going to come into your network whether you like it or not," Driver said. "It has become completely impractical to avoid the subject at all."

Open source isn't quite as good as some of its proponents would have you believe, and not as dangerous as some detractors might suggest, Driver said. The important thing is to plan an open source strategy, to set guidelines on where and when open source products are to be used. IT shops are scrambling to set open source policies, but almost no one has implemented one with any teeth, he said. It's better to avoid open source altogether than to not supervise its adoption with something like a don't ask, don't tell policy, according to Driver. "You've got to know what's in your organization. If you can't manage it, you can't control it," he said.

Some believe you always can get better quality and lower total cost of ownership with open source. But users who think that's always true are "going to be sorely disappointed," Driver said.

Open source adoption decisions should be based on four factors viewed collectively, Driver said. The first factor is whether the software fits its purpose. This may seem obvious, but some open source proponents exaggerate its capabilities. "Open source, more than anything else in the industry, has a large set of proponents who border on zealots," he said. "It's the guy who says, 'Windows sucks, it doesn't work. Let's throw it out and use Linux.'"

The second factor is whether the open source product is mature enough to provide an acceptable risk/reward ratio. Are there services and vendors standing behind the product?

The third factor is the company's technology adoption profile. Is it comfortable with bleeding-edge technologies? Does it always require third-party support? How much internal capability does it have to support the product?

The fourth factor is whether the deployment scenario is mission-critical. If the application absolutely has to run every minute of the day, make sure the software meets your requirements. That's not to say open source can't be used for mission-critical programs. Deployment patterns show it is, Driver said. "It's being used by increasingly more conservative companies and for increasingly mission-critical solutions," he said.

Customers may worry about fragmentation, because there can be many different versions of such open source programs as Linux. A form of natural selection prevents massive fragmentation across the open source community, however, Driver argued. "There isn't any guarantee that Linux won't fragment tomorrow," he said. Some fragmentation is okay, because monopolies in open source are not desirable. "Natural selection weeds out weaker competing variations. Yet, specialization allows variations to coexist as well," he said. "Thus, specialization is an incredibly important feature of open source."

Driver said he's run into many people who argue that freely available source code is going to put Microsoft out of business in five years. He finds the notion laughable. While open source is changing the commercial software industry, the industry itself is changing what we think of as open source software. Some commercial vendors embrace open source to gain competitive advantage. "Why does IBM love Linux?" Driver asked. "These days, they like it because it hurts Microsoft."

In some cases, commercial vendors are corrupting the ideals of the open source movement. Some vendors use what Driver called a "gated source" model, where they give customers the right to alter code for their own use but prevent code from being redistributed. Basically, "the vendor says 'I'm not going to give you any of the freedoms that impact my ability to create commercial monetization of the product,'" Driver said. That's why it's important to agree on a definition of open source. Gartner considers software open source only when it has been granted a license, such as the General Public License.

"We do not believe open source should devolve into yet another marketing term," Driver said. "That would be a bad thing."