3) Facebook runs out of ideas for monetizing the Facebook platform: In their own words: "We currently monetize the Facebook Platform in several ways, including ads on pages generated by apps on Facebook, direct advertising on Facebook purchased by Platform developers to drive traffic to their apps and websites, and fees from our Platform developers' use of our Payments infrastructure to sell virtual and digital goods to users. Apps built by developers of social games, particularly Zynga, are currently responsible for substantially all of our revenue derived from Payments."
4) Foreign "Facebooks" eat Facebook's lunch overseas: With 800 million users, Facebook considers itself one of the largest "nations" in the world. But one size doesn't fit all in social media. Various countries have different leading search engines and social apps that adhere tot the peculiar contours of the local culture. Those cultural differences don't seem to have stopped Facebook's growth, but if foreign social media networks create new features that mesh with large populations and resist acquisition by Facebook, Zuckerberg will have competition. From Facebook: "We compete ... with other, largely regional, social networks that have strong positions in particular countries, including Cyworld in Korea, Mixi in Japan, Orkut (owned by Google) in Brazil and India, and vKontakte in Russia. We would also face competition from companies in China such as Renren, Sina, and Tencent in the event that we are able to access the market in China in the future."
5) Google eats Facebook's lunch: Facebook's biggest threat probably isn't some foreign network like Cyworld that you haven't heard of. It's probably the tech company you've heard of the most: Google. It already dominates search, has hundreds of millions of people signed up on a social media network, and owns a big slice of the smart phone market: "Certain competitors, including Google, could use strong or dominant positions in one or more markets to gain competitive advantage against us in areas where we operate including: by integrating competing social networking platforms or features into products they control such as search engines, web browsers, or mobile device operating systems; by making acquisitions; or by making access to Facebook more difficult."
6) Facebook loses a top lieutenant or hires too many people: "We cannot assure you that we will effectively manage our growth," the IPO states, noting that its workers have grown from from 2,127 at the end of 2010 to 3,200 on December 31, 2011. The document also notes that the departure of COO Sheryl Sandberg could hurt the company's momentum. Sandberg's value to the company is made apparent in her salary: $31 million last year.
7) Facebook's reputation suffers: Facebook's history of privacy concerns is nearly as long as the history of Facebook. After all, this is a company whose business model relies on collecting and selling disaggregated user data to advertisers. Zuckerberg is aware of the risk this poses to both to users and advertisers: "Maintaining and enhancing our brand will depend largely on our ability to continue to provide useful, reliable, trustworthy, and innovative products, which we may not do successfully. We may introduce new products or terms of service that users do not like, which may negatively affect our brand. Additionally, the actions of our Platform developers may affect our brand if users do not have a positive experience using third-party apps and websites integrated with Facebook."