Sometimes, you mix two trendy topics, and all you get is a mess. For instance, combine Mel Gibson and the Old Spice Guy, and you'd have one nasty set of viral videos. But other times, two buzzworthy themes combine perfectly, like the bacon craze and artisan ice cream.

OpenStack, a new open source cloud computing initiative, is like the porcine ice cream.

The new collaboration of 25 companies including large hosting service Rackspace and NASA is trying to open up cloud computing, which has been dominated by Amazon's extremely successful and proprietary EC3 service.

Tech heavyweights lined up behind the project for its launch today, including the influential Tim O'Reilly.

"If cloud computing is the future, then understanding how to make that future open is one of the great technology challenges of our day," O'Reilly said. "Rackspace and NASA are taking an amazing step towards my vision of an open cloud future."

Here's why this is important: cloud computing is the idea that people (or corporations or governments) purchase computation as a service instead of buying and maintaining computers has been one of the dominant themes of the last several years. To simplify: Gmail is hosted in the cloud. You don't store messages on your machine; you just retrieve them when you need them.

But there could be some problems with the cloud. Very few companies using proprietary technologies will become the possessors of much of the world's data. ""'The cloud' is a dirigible filled with hydrogen, with pictures of clouds painted on the side," designer Mickey McManus said to James Fallows at a panel this month. What he meant, Fallows explained, was that "we are collectively cruising for a bruising in entrusting so much of humanity's  knowledge and affairs to so few online storage sources."

And that's where OpenStack comes in. By creating an open source project and pushing for open standards, people and companies will be able to switch more easily between services, taking their data with them. The marketplace could be more competitive and potentially more secure with risk spread over a greater number of companies.

"If you look at other parts of the technology industry, people are able to change providers if the company doesn't fit their needs," said Jonathan Bryce, founder of Rackspace Cloud, one of the partners in OpenStack. "In the cloud, it hasn't been that way because there the systems are proprietary."

One fascinating component of the project is that the cloud code base was developed and then released by NASA under a standard open source license known as Apache. That meant both Rackspace and NASA can use the publicly developed technology. The two entities already are using the Nebula platform OpenStack technologies to store petabytes (that's one million gigabytes) of stuff.

The open source coalition will have plenty of competition, though. Beyond Amazon, both Microsoft and VMWare are trying to develop cloud platforms.