Pandora, the personalized Internet radio service, has filed to go public in mid-2011 and could raise as much as $100 million when it does. What insights does the IPO paperwork provide about the company and what's in store for users?

Popularity Doesn't Necessarily Translate Into Profitability

Pandora's registered users grew from 22 million in 2009 to a whopping 80 million in 2011. In fact, the company is now adding a new registered user every second. But Pandora still isn't profitable, though it's getting close and believes it can turn a profit as early as 2013.

Perhaps nothing stands in the way of profitability more than the copyright fees that Pandora pays to organizations representing record labels, songwriters, and composers, which consume half of the company's revenues. And the more popular Pandora gets, the more expensive these royalty fees become. As the company explains in its filing, "If we cannot successfully earn revenue at a rate that exceeds the operational costs associated with increased listener hours, we may not be able to achieve or sustain profitability."

Pandora's Mobile Strategy Is Vulnerable

Pandora's expansion into mobile devices has largely fueled its recent growth, but the strategy also places the company at the whim of mobile device or operating system makers like Apple that compete with Pandora. In its SEC filing, Pandora warns that its success could be compromised if it loses access to mobile platforms for competitive reasons.

Free Service Not Going Anywhere

Pandora currently makes 86 percent of its revenue from advertising and the remainder from a subscription service that provides users with an ad-free, higher-quality listening experience. VentureBeat's Anthony Ha believes that emphasis isn't likely to change anytime soon: "When listing the key elements of 'building a successful long-term business,'" he notes, "the filing mentions new ad products but nothing related to subscriptions."

Web Capacity a Concern

Pandora is worried that more listeners tuning in more frequently could make the Internet and wireless networks "congested." The company also expresses concern that wireless communications companies will raise their rates or impose data usage limits on their networks, discouraging people from using its service.

Pandora Might Soon Offer More Than Music

The company says it's exploring an expansion into other content areas like sports, talk, and news. It didn't say whether it will extend the technology that fuels its music recommendation engine to these other forms of content.

Would You Like Pandora as Much If It Were Called The Savage Beast?

According to the filing, Pandora was incorporated in California in 2000 as TheSavageBeast.com. Only in 2005 did it become Pandora.