RENEE MONTAGNE, HOST:
When a company files to go public, it has to lay out in black and white the biggest risks faced by that company - what could undermine its business model, for instance, or if a key executive plans to leave - anything that could put investors' money at risk. Even though executives are required to do this by law, it can run to many single-spaced pages. It can also make great reading, as NPR's Steve Henn found out with Facebook.
STEVE HENN, BYLINE: So I've been flipping through Facebook's IPO filing. And by far my favorite section is labeled Risk Factors. Sure, there's some gobbledygook, but just the part on mobile advertising is fascinating, if you pull it apart. Roughly half of Facebook's users check in on mobile devices every month, but so far the company isn't making any money on mobile.
JULIE ASK: Mobile is a very small screen.
HENN: Julie Ask is at Forrester Research. She says mobile ads are tough to do right.
ASK: So it's not as if I'm on my PC and there can be advertising on the top or on the side and I can ignore it and still do what I want to do. On a small screen, it's right in front of my face.
HENN: A bad mobile ad can muck up the entire Facebook experience.
ASK: I'm glad that Facebook isn't making any money on their mobile services for Facebook.
HENN: As a customer, Julie Ask might be happy, but as a business this is a problem Facebook's got to solve. The markets where it needs to grow, like India, Russia and Brazil, are dominated by mobile devices. Last year smartphones outsold PCs for the first time ever. Your phone knows where you are and where you're going. It might know you better than your own mother.
ASK: I use my phone to bank. I use my phone for Facebook. I use my phone to shop, to change the channel on my TV at home. I read books, I listen to music.
HENN: If Facebook doesn't figure out how to make money on mobile advertising, someone else will. Advertisers are salivating. But...
ASK: If you think about all the things Facebook knows about us...
HENN: And what else it can learn using our phones...
ASK: ...I think it can begin to seem a bit creepy.
HENN: And that brings us to another big risk facing Facebook's business: privacy.
JEFF CHESTER: Privacy is Facebook's Achilles' heel.
HENN: Jeff Chester is a privacy advocate at the Center for Digital Democracy. He says Facebook's facing increasing scrutiny in Europe over its privacy policies, and the company's executives know new regulations there could tie it in knots.
CHESTER: Facebook has to walk a very difficult digital tightrope.
HENN: It has to placate regulators, convince to us keep sharing more and more information, while at the same time building new products that sell billions of dollars in new kinds of highly targeted ads. Julie Ask says for all that to work, you'd have to trust Facebook almost completely. If it knows as much about you as your mom, you'll need to think about it like your mom.
ASK: So what Facebook is going to have to do is make this seem less like Big Brother - less creepy - and more like Big Mother - somebody or something that's looking out for me, that's helping me make good decisions.
HENN: Ask says that's going to be a tough sell. For a company, any company, inspiring that kind of trust is an enormous challenge. She says pulling it off will require a team of brilliant, sensitive social engineers working their butts off. And that brings us to perhaps my favorite risk factor in Facebook's 186-page prospectus. After the IPO, the company's top executives are worried that many of their best and brightest employees will really be too rich to care.
VIVEK WADHWA: So that is a real risk factor.
HENN: Vivek Wadhwa is a fellow at Stanford law school.
WADHWA: These are young kids we're talking about, typically in their early 20s. Suddenly they have more money than they ever dreamed about.
HENN: And that may make staying up all night to work on the next great social app a whole lot less appealing. Steve Henn, NPR News, Silicon Valley.