There is a lot we don’t know about Google’s cellphone effort, but this much seems clear from the many reports: Google isn’t making a phone, it is developing an open-source cellphone operating system. Google will, no doubt build some proprietary applications that run on it, find manufacturers and cut deals with carriers to deliver a shiny package to consumers.

Another interesting fact: Mike Schroepfer, the vice president for engineering of the Mozilla Foundation, announced that the group is working on a mobile version of its open-source Firefox browser.

But consider how dissonant the first part is: open source and cellphone. As these and other open-source initiatives move forward, we will see far more challenges to the existing structure of the wireless industry.

Mostly, cellphones have been closed environments, with a behind-the-scenes battle for control between the carriers (who have power in the United States) and the handset makers (who have a bit more power in many other countries).

There are some open elements on some phones. Many of the rudimentary browsers can reach rudimentary mobile Web sites. And some phones allow Java applications to run. (On my little Samsung flip phone, a few of the decent things I can do are Java apps for Google maps, Gmail, Citibank banking and such.)

The reason for these limits is the intersection of economics and psychology: People want a low upfront price for their phones. But it turns out that many will pay a lot of money to add features later. I wrote yesterday about the $9.99 monthly fee that Verizon charges to use the GPS technology that is already in your phone. And think that many people pay as much as $3 for a 30-second ringtone from a 99-cent song.

A truly open phone would allow you use any of its features and play any music you owned when it rang without paying an additional toll. Of course, it may well cost more up front too.

But Moore’s Law and its corollaries promise that cost will become less of an issue. Meanwhile, the capabilities of mobile devices are multiplying. In his blog post, Mr. Schroepfer wrote that a full Firefox browser, with plugins and such, is going to be possible for mobile phones because of rapid advances in mobile computing power.

The single most important thing about the iPhone is that it gives us a vision of what these devices will be able to do and an interface that will allow people to use them.

That’s why I find the battle between Apple and the hacker community over the capabilities of the iPhone so interesting. Apple has some good reasons for trying to keep control over the iPhone. A cellphone has to be reliable, and in these early days, Apple has an interest in keeping its platform safe from bugs and malware.

This is one of the constant fault lines in technology: stability versus innovation. And the demand for innovation around mobile computing is like water massing at the top of Niagara Falls.

Google has been pushing for openness in the Washington jockeying over the auction for the UHF television frequencies. And it will open another front in this war with its open-source phone operating system.

That said, Google may have a hard time in the United States. The most natural distributor for a phone running its OS is Verizon, which is locked out of the iPhone market. But Verizon has been the biggest opponent of Google’s vision of open spectrum. You can imagine all sorts of compromises from all sides to get a deal done. And Google may have to offer the carriers more control than it wants to, just as Apple had to accommodate AT&T.

But it may well be that Google’s OS takes off faster outside of the U.S. Many countries, after all, have more of a market for unlocked phones as well as faster adoption of mobile data services. And Google has rapidly growing advertising networks in Europe and Asia that could profit well from piggybacking its services on these phones.

This may well be good for consumers in the United States anyway. Rapid adoption of an open-source phone environment will help drive down costs and create applications that doubtless will eventually migrate here.

The handset makers, I suspect, are of mixed opinions on this. Nokia, and perhaps a few other big players, would like to profit from software and services, as Apple is. But there are enough other companies, like HTC, that are mainly in the volume manufacturing business, who would like nothing better than a free supplier of sexy software.