The Linux Mobile Foundation, or LiMo, has been trying to create an open-source platform for device manufacturers, carriers, third-party application developers and others in the mobile industry since last year. By using the open source Linux operating system, companies across segments of the mobile industry will have lower technical and cost barriers to mobile operating system innovation, the effort hopes.

Today, LiMo has gotten a big boost, maybe: Eight new member organizations have joined, including the largest US carrier, Verizon, and Firefox browser creator, Mozilla.

LiMo goes to great pains to bring everybody under its tent. Its members provide intellectual property to its “middleware” platform — the operating system of a phone, rather than its applications and content. See screenshot for a diagram of the components that LiMo works in (in green); LiMo background information PDF here.

At its core, LiMo seems to be pitting carriers like new LiMo member Verizon against the Google-led Android effort, even though they’re not quite the same thing — both Google and incumbent carriers hope to maintain some control over operating systems on their phones, so they can promote their own ads and applications.

LiMo, for example, will allow carriers like Verizon to cut the cost of putting together an operating system. It lets carriers customize their own user interfaces for the LiMo operating system, as Linux Watch points out, which is a way for these companies to introduce applications that they can control and make money from.

The closest rival here is the Open Handset Alliance, or OHA, led by Google, that is implementing the Google-developed Android operating system — based on a different distribution of Linux. In contrast to LiMo, Android has its own user interface. Through this interface, Google will give preference to its own ads and applications like Gmail and Google Maps, as well as partner third-party applications.

Mobile Linux is arriving, but for whom?

Mobile Linux operating systems has until recently been viewed skeptically with the mobile industry. They haven’t gained much traction among more expensive and complex “smartphones.”

But the competition to be more open, spurred by Android, has forced carriers like Verizon to look at ways of giving developers more control. The catch is that everything still being developed. There are only a few LiMo-enabled phones out now (like the Motorola U9, pictured, via Linux Devices), and the first Android phone won’t be out until later this year.

Long-term, though, mid to high-range Linux-based phones are expected to reach twenty percent worldwide market share by 2013, according to one study. Meanwhile, the other competitors have grown large. Apple is seeing surging purchases of its iPhone, which runs on its own operating system — a study from last fall says the iPhone has already gained 27 percent of the smartphone market in the U.S.

And, of course, the largest hardware manufacturer in the world, Nokia, already has its own operating system, Symbian. Microsoft’s mobile version of Windows has also already become popular on high-end “smartphones” that allow better web access. LiMo hopes to be a cheaper, jointly-controlled alternative.

Where does all this talk of open efforts leave third-party developers? First of all, it will ultimately create new ways to build applications that