4 Questions for Pandora Media Inc (P)

Pandora Media Inc (NYSE:P)‘s rocking and rolling these days.

The leading music-streaming service may be trading 25% below its 2011 IPO price of $16, but the shares have rallied nearly 70% since bottoming out in November.

Despite the rally, there are plenty of questions about Pandora’s business and its model’s potential as we head into Thursday’s quarterly report.

Let’s go over a few of the pertinent questions, including some that will likely be answered after Thursday’s market close.

1. Is sequential growth resuming after a soft January?
One of the bigger negative surprises at the company that pioneered the music-discovery niche is Pandora’s sequential slide in active users for the month of January. Pandora Media Inc (NYSE:P) went from 67.1 million active listeners in December to just 65.6 million users a month later.

There are seasonal aspects at play, but active listeners didn’t slip between December 2011 and January 2012.

The number of hours streamed also remained flat at 1.39 billion in this past December and January. There was a sequential uptick a year earlier.

Pandora Media Inc (NYSE:P) should provide its metrics for February this week. There was a healthy sequential increase in active users and listener hours last year, and it would be problematic if this changes. Sure, Pandora Media Inc (NYSE:P) would still be posting hearty year-over-year growth despite a sequential decline, but it would give more ammo to the argument that Pandora’s service may be peaking.

2. Why did it start capping free mobile usage?
Pandora’s problem has always been that the vast majority of its users are freeloaders.

Just 11% of the dot-com speedster’s revenue came from subscription revenue in its latest quarter. That’s a sharp contrast to Spotify and Sirius XM Radio Inc (NASDAQ:SIRI) , which rely primarily on premium accounts.

One can rightfully argue that Pandora wouldn’t be as popular if it wasn’t consumed largely as a free ad-supported service, but the company is taking baby steps in that direction with last week’s decision to cap free usage through mobile devices at 40 hours a month.

The timing is peculiar. Pandora is coming off a rare sequential slide in active listeners, and premium competition is starting to heat up. Sirius XM introduced personalized radio to enhance its streaming offering earlier this year, and Apple Inc. (NASDAQ:AAPL) is widely rumored to be diving into this market soon.

3. Is advertising revenue still growing faster than subscription revenue?
As hard as it is for any music-streaming company to monetize digital content, Pandora’s struggling even harder to grow its subscription revenue.

In its latest quarter, for example, ad revenue climbed 61% but subscription revenue rose by just 52%.

Sure, most companies would kill for 52% in subscription revenue growth. Sirius XM is naturally growing a lot slower, and even renewed market darling Netflix, Inc. (NASDAQ:NFLX) has only grown its sub revenue by 8% over the past year.