Mark Zuckerberg, a 19-year-old Harvard computer whiz, begins working out of his dormitory room on an online network. A month later, he launches "thefacebook" with classmates Chris Hughes, Eduardo Saverin and Dustin Moskovitz.
MAY: Zuckerberg moves to Silicon Valley, decides not to return to Harvard for the fall semester.
JULY: Facebook get $500,000 investment from PayPal co-founder Peter Thiel.
2005
APRIL: Facebook gets a second round of funding: $12.7 million from Accel Partners.
AUGUST: Thefacebook.com changes its name to Facebook.
2006
FEBRUARY: Viacom offers to buy Facebook for $1.5 billion. Yahoo! also makes an unsuccessful $1 billion bid.
2007
OCTOBER: Microsoft invests $240 million in a deal that values Facebook at $15 billion. Membership tops 50 million.
2008
FEBRUARY: A $65 million settlement is reached with twins Tyler and Cameron Winklevoss over allegations that Zuckerberg stole their idea. Facebook launches a Spanish site.
MARCH: French and German sites are launched.
APRIL: Facebook dethrones MySpace as the world's most popular social network.
AUGUST: Membership hits 100 million. 2009
MARCH: Facebook launches the first mobile application.
MAY: Russia's Digital Sky Technologies invests $200 million.
SEPTEMBER: Zuckerberg says the firm has become "cash flow positive."
2010
MAY: Pakistan blocks access to Facebook over a competition encouraging users to post caricatures of the Prophet Mohammed (PBUH).
JULY: Membership hits 500 million, including Lady Gaga and President Barack Obama.
DECEMBER: Time magazine names Zuckerberg "Person of the Year" for "transforming the way we live our lives every day."
2011
JANUARY: A private share offering raises $1.5 billion, values Facebook at $50 billion.
FEBRUARY: Facebook announces plans to move from Palo Alto to former home of Sun Microsystems in Menlo Park.
2012
JANUARY: Facebook files for initial public offering.
MAY: Membership hits 900 million, regulatory filings show. The IPO is priced at $38 per share, giving Facebook a market value of $104 billion and raising at least $16 billion.