Are Pandora Media's (NYSE:P) latest numbers all they're cracked up to be?

In the Internet radio star's latest report on audience metrics, Pandora fans and foes can each find numbers to reinforce their biases. For the company's fans, the company confirmed that audience growth continues apace.

Total listener hours in October were up 18% year over year to 1.47 billion hours. That's almost precisely the same rate of growth that we saw at Pandora in September. It continues a pretty long-term trend of Pandora growing in size, and gaining in market share. Indeed, according to the company, it tacked on more than a full percentage point of radio market share in October, growing to control 8.06% of the market.

And yet, there are a couple of numbers in Pandora's report that appear to offer reason for worry. For example, listener hours were up 18%, but total listeners to the company's multiple radio "channels" grew 20%. This suggests that new listeners aren't tuning in for as many hours of music -- and ads, and ad sales -- as they used to.

Also worrisome: Pandora's 70.9 million active listeners in October 2013 may have been more than they were in October 2012 -- but they were fewer than tuned into the company's offerings just one month ago. September active listeners totaled 72.7 million.

Should this scare you?
Maybe, maybe not. On one hand, a 2.5% decline in the number of folks listening appears to buck the company's historical growth trend. If these listeners are also listening less often, and so are less loyal to the service, then this might compound the worries.

On the other hand, though, Pandora did still say that despite the decline in listeners, it increased market share -- not just year over year, but sequentially. How is that possible?

A recent report out of NielsenĀ may provide the answer. Discussing the effects of seasonality on radio audiences, Nielsen noted that sports radio is generally "dead" in the months of summer, but with the advent of football season and the run-up to the World Series in baseball, sports radio "recorded significant increases in listener shares again in October." Indeed, sports radio "set an all-time high this month for audience shares," producing growth in "double-digit percentages across all three age ranges" that Nielsen monitors.

Foolish takeaway
This, Fools, may be the key to the question, and the reason investors today are buying up Pandora shares hand over fist. A few sports junkies may have defected from Pandora's music offerings to tune into the NFL and MLB in October -- temporarily. But the long-term trend remains intact. Pandora's share of the radio market continues to grow.

Fool contributor Rich Smith has no position in any stocks mentioned. The Motley Fool recommends Pandora Media. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.