In its IPO filing with the SEC, Facebook spells out “risk factors” for potential investors:

“Our business is subject to numerous risks described in the section entitled “Risk Factors” and elsewhere in this prospectus. You should carefully consider these risks before making an investment. Some of these risks include:

• If we fail to retain existing users or add new users, or if our users decrease their level of engagement with Facebook, our revenue, financial results, and business may be significantly harmed;

• We generate a substantial majority of our revenue from advertising. The loss of advertisers, or reduction in spending by advertisers with Facebook, could seriously harm our business;

• Growth in use of Facebook through our mobile products, where our ability to monetize is unproven, as a substitute for use on personal computers may negatively affect our revenue and financial results;

• Facebook user growth and engagement on mobile devices depend upon effective operation with mobile operating systems, networks, and standards that we do not control;

• We may not be successful in our efforts to grow and further monetize the Facebook Platform;

• Our business is highly competitive, and competition presents an ongoing threat to the success of our business;

• Improper access to or disclosure of our users’ information, or violation of our terms of service or policies, could harm our reputation and adversely affect our business;

• Our business is subject to complex and evolving U.S. and foreign laws and regulations regarding privacy, data protection, and other matters. Many of these laws and regulations are subject to change and uncertain interpretation, and could harm our business;

• Our CEO has control over key decision making as a result of his control of a majority of our voting stock;

• The loss of Mark Zuckerberg, Sheryl K. Sandberg, or other key personnel could harm our business;

• We anticipate that we will expend substantial funds in connection with tax withholding and remittance obligations related to the initial settlement of our restricted stock units (RSUs);

• The market price of our Class A common stock may be volatile or may decline, and you may not be able to resell your shares at or above the initial public offering price; and

• Substantial blocks of our total outstanding shares may be sold into the market as “lock-up” periods end, as further described in “Shares Eligible for Future Sale.” If there are substantial sales of shares of our common stock, the price of our Class A common stock could decline.”

Facebook’s Growth

Facebook’s growth over the years, as compiled by The Associated Press with data provided by Facebook:

December 2004: 1 million.

December 2005: 5.5 million.

December 2006: 12 million.

April 2007: 20 million.

October 2007: 50 million.

August 2008: 100 million.

January 2009: 150 million.

February 2009: 175 million.

April 2009: 200 million.

July 2009: 250 million.

September 2009: 300 million.

December 2009: 350 million.

February 2010: 400 million.

July 2010: 500 million.

December 2010: 608 million.

July 2011: 750 million.

September 2011: 800 million.

December 2011: 845 million.

March 2012: 901 million.