Six months after Apple (Nasdaq: AAPL) unveiled its FaceTime video calling service, the offering remains closed to third-party vendors despite a pledge by CEO Steve Jobs to offer up the FaceTime specification to the market at large. However, it appears there is little interest among video calling vendors for interoperability of any kind: I asked leading mobile video calling firms Skype, fring and Qik whether they interoperate with each other -- or any other video calling services -- and the unanimous answer was "no."

This year could be remembered as the jumping-off point for mobile video calling. Apple this summer heavily promoted its FaceTime video calling service in its iPhone 4 marketing. Sprint Nextel (on its HTC Evo, powered by Qik) and T-Mobile USA (on its myTouch 4G, also powered by Qik) also trumpeted the feature. Indeed, T-Mobile used its 3G-capable video calling service to poke fun at AT&T (NYSE: T) Mobility's network, due to the WiFi-only nature of FaceTime.

However, it appears that all U.S. video callers remain stuck in the silos of their respective providers. As far as I can tell, Apple has not yet released its FaceTime specification, thus ensuring the only mobile video calls are among iPhone 4 users. (Apple did not respond to my questions on whether the FaceTime specification has been released -- which again raises the question why Apple bothers to even operate a PR department.)

Skype and fring used to interoperate until the companies had a well-documented falling out earlier this year. A fring representative said that the company is open to interoperating with FaceTime, but noted "we have yet to see the specs so this is premature." Separately, a Skype representative confirmed the company does not interoperate with any other video calling service.

For its part, Qik declined to discuss possible interop plans with FaceTime, but Qik's marketing chief Allyson Campa did say that, "Qik is an open platform and we intend to interoperate wherever possible."

So where does this leave the video-calling market? First, I suspect few mobile users who have access to video calling technology even use the service. And for those who do, I'm guessing they only have a few people they would video call anyway. For example, my wife and I own video calling-capable smartphones that can talk to each other, but we've only used the feature once or twice. However, my kids seem to like it.

The situation reminds me of the early days of text messaging in the United States. In 2001, AT&T Wireless (the one before Cingular and AT&T Mobility) opened up its network to text messages from rivals' networks, an action that quickly cascaded into the seamless texting environment Americans now enjoy. The same problem also hampered the market for picture messaging, for a time.

I realize the mobile video calling market is in its infancy, and interoperability troubles often plague nascent technologies. Indeed, some instant messaging applications are still relatively siloed. However, I'm betting that wireless carriers understand the benefits of interoperability, based on the massive success of text messaging, and I would expect interoperable video calling to catch fire sooner than later.

This article originally published here. Get your wireless industry briefing here.

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