Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Internet radio service Pandora Media (NYSE: P) surged 18% today after its quarterly results and guidance easily topped Wall Street expectations.

So what: Pandora's third-quarter loss widened to $5.4 million, but an impressive 51% jump in revenue, coupled with upbeat guidance for the full year, suggests that management's growth strategy is right on track. In fact, mobile advertising revenue spiked a whopping 86%, while the company nabbed more market share (its share of U.S. listeners grew from 3.5% to 6%), momentarily easing concerns over rapidly increasing competition in the space.

Now what: Management now sees full-year revenue of $425 million to $432 million, up from its prior view of $420 million to $427 million. "Our market share gains and advertising revenue growth continue at an extraordinary pace," Chairman and CEO Joe Kennedy said in a conference call. "Our scale, coupled with our products unique advertising capabilities give Pandora an advantage in capturing an outsize share of media buying from advertisers as they shift their spending from traditional forms of media to online and mobile." Until that supposed edge over the competition translates into positive cash flow growth, however, Pandora remains a particularly speculative selection. 

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