When I talk to people about Linux and FLOSS, many times they ask me "That's interesting, but how can you make money with it?" Hewlett-Packard seems to have figured it out. This article from NewsFactor.com tells the story:

"The revenue figures from HP are not surprising, Yankee Group analyst Dana Gardner told NewsFactor. The role of Linux for mainline enterprise
organizations is growing rapidly, in large part because of greater
control and trust associated with the technology, he said.

"The perception of open source has changed. Businesses now recognize that Linux is ready for prime time," he said, adding that the latest products from HP, IBM, Red hat and SuSE have allayed most fears. "In many cases, Linux is recognized as a hedge against lock-in, with more freedom to control how software works in the enterprise."

But the best quote from the article, again from Dana Gardner, is this: "Clearly, there is a great deal of residual business around the technology." 2.5 billion greenbacks is quite a bit of residue.