For the first time in more than a month, shares of Sirius XM Radio (Nasdaq: SIRI) slipped below the $2 mark yesterday.

Hitting an intraday low of $1.98 just minutes before closing at $2.03 may be disappointing to those who got in when the stock hit a two-year high of $2.42 last month, but you won't find too many of those who got in during 2009 or 2010 bellyaching.

When the stock bottomed out at a mere nickel in February 2009, even the most ardent of bulls weren't predicting the kind of profitability and share prices that we're now experiencing. Analysts see Sirius XM earning $0.04 a share this year and $0.06 a share come 2012. Who wouldn't have bought into the satellite radio for $0.05, knowing what the company would be earning just two and three years later?

Of course, no one knew. Liberty Capital's (Nasdaq: LCAPA) timely infusion and Cash for Clunkers' success in breathing new life into car sales finally turned Sirius XM into the company longtime investors thought they were buying into years ago.

So what's behind the recent weakness? Profit-taking and a weak May for automakers are the culprits, though the catalysts for a bullish turnaround aren't too far away. Sirius XM 2.0 -- the next generation of interactive satellite receivers -- will hit the market later this year. The inevitable monthly subscription hike should materialize early in 2012.

These two moves will justify a higher market cap than today's $13 billion price tag if they go over well. If Sirius XM 2.0 introduces new revenue streams, or if next year's rate hike doesn't result in a spike of cancellations, how can Sirius XM not continue higher? Revenue growth will accelerate, and profit margins will widen.

However, volatility will remain Sirius XM's middle name. Investors know that going in, or their certificates don't say Sirius Volatility XM.

Now that Sirius XM is at $2.00, is its next stop $1.50 or $2.50? Share your thoughts in the comment box below.

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Longtime Fool contributor Rick Munarriz is a subscriber to Sirius since 2004. He does not own shares in any of the stocks in this article. He is also a member of the Rule Breakers analytical team, seeking out the next great growth stock early in its defiance.