In his first live show since Thursday's debut of the Sirius XM Premium Online application through Apple's (NASDAQ:AAPL) App Store, Howard Stern explained the absence of his signature Howard 100 and Howard 101 channels on the new smartphone offering.

In a nutshell, it was a "contractual rights thing" that may -- or may not -- be corrected.

Despite the glimmer of hope that he may eventually join the streams for iPhone and iPod touch owners, it seems unlikely at this point. Stern is savvy enough to negotiate publicly, through his show, but let's try to imagine what Mel Karmazin, Sirius XM Radio's (NASDAQ:SIRI) CEO, might be thinking.

Why would Karmazin have launched the app without Stern on board? Obviously, its best chance at success would have been with Stern available. But when Stern discusses "contractual rights," he's probably talking about money. His original contract clearly doesn't mention anything about premium mobile applications, and he either wants more money or is using his on-air comments as a tool to negotiate a contract extension under healthy terms. His five-year, $500 million satellite-radio deal is over at the end of next year. If the roadblock is that iPhone streaming would conflict with his "on demand" television deal, that problem can still be solved financially.

However, by not spending the money now, Karmazin is unlikely to meet Stern's demands later. After all, if the app becomes a hit without Stern, Sirius XM will argue that it doesn't need the popular morning-show host. But if the app bombs, paying up for Stern may be too little, too late for Sirius XM.

Then again, maybe Karmazin and Stern see what others have failed to consider: What if Stern has plans to either retire at the end of next year or just go it alone?

"Sirius is great, even without us," Stern told his listeners yesterday. That doesn't sound like someone negotiating for a bigger paycheck. Stern has no problem telegraphing his moves early, either. He signed his Sirius contract in the fall of 2004, while he still had another year and change to go under Viacom's (NYSE:VIA) terrestrial-radio wing.

Retirement is certainly a possibility. Stern should have plenty of money socked away. His current show schedule is already light -- just four shows a week, with several weeks off during the year -- so he's unlikely to get an even softer schedule come 2011.

If Karmazin and Stern are on the same page in terms of anticipating his retirement, it wouldn't make sense for Karmazin to pay up for Stern's presence on the app.

The more tantalizing option, of course, is that Stern is ready to break out on his own. The success of Internet radio apps will make satellites unnecessary in a smartphone future. He can launch his own premium network and broadcast into computers everywhere. The smartphone audience will also get bigger as Apple, Research In Motion (NASDAQ:RIMM), and Palm (NASDAQ:PALM) will command even larger audiences in 2011.

On his own, Stern could also make his network available internationally. Even on the globally available iPhone, Sirius XM is restricted to stateside listeners. Stern wouldn't have the same licensing hoops to jump through on his own.

Is Stern ready for a third revolution, though?  

Turn up these other satellite-radio headlines:

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Longtime Fool contributor Rick Munarriz is a subscriber to both Sirius and XM. He owns no shares in any of the companies in this story and is also a member of the Rule Breakers analytical team, seeking out the next great growth stock early in its defiance. The Fool has a disclosure policy.