After a tough few months of royalty-based criticism, Pandora had some good news yesterday: a quarterly profit.

The company reported its Q3 financials, with revenues up 60% year-on-year to $120m, and a net profit of $2.1m compared to a loss of $7.9m this time last year. Pandora had 62.4m active users at the end of November, who listened to 1.27bn hours during that month.

How did analysts take the news? Not well. In fact, Pandora’s share price dropped 19% after the financials announcement. Why? Because the company predicted slowing growth in the next quarter, and a return to net losses.

“Many of our advertisers have recently become more cautious about their near-term spending, including their plans for January as macroeconomic concerns, including the fiscal cliff, have increased,” CEO Joe Kennedy told analysts. Cue stock plunge.

The results did provide more information on the continued importance of mobile for Pandora. Mobile and other connected devices now account for 77% of total listening hours, but the company is also doing a better job of making money from this usage: Pandora’s mobile revenues jumped 112% year-on-year to $73.9m.

The launch of version 4.0 of its iOS and Android apps, which includes improved sponsorship opportunities for advertisers, appears to be paying off. Another stat of note: 1m people are using Pandora through its integration deals with car-makers. But Kennedy also unsurprisingly banged the gong for the Internet Radio Fairness Act:

“There is no country internationally where the entire radio industry, all of the AM, FM, satellite, cable and internet radio companies, pays a total combined amount even close to what we as a single company will pay this year,” said Kennedy.