Mark Zuckerberg, Chris Hughes, Andrew McCollum, Dustin Moskovitz and Eduardo Saverin start Facebook as sophomores at Harvard University.
Facebook begins expansion to other colleges and universities.
June - September 2004
Facebook moves headquarters to Palo Alto, Calif. Site introduces the Wall, which allows people to write personal musings and other tidbits on their profile pages.
A lawsuit is filed against Facebook claiming that Mark Zuckerberg stole the idea for the site from a company co-founded by twins Cameron and Tyler Winklevoss and Harvard classmate Divya Narendra.
September 2005 - 2006
Facebook expands to include high schools. A year later, Facebook introduces work networks, allowing people with a corporate email address to join.
Facebook begins letting anyone over 13 join. It also introduces News Feed, which collects friends' Wall posts in one place. Although that led to complaints about privacy, News Feed became one of Facebook's most popular features.
Facebook launches "Platform," a system for letting outside programmers develop tools for sharing photos, taking quizzes and playing games. The system creates a Facebook economy and allows companies, such as game maker Zynga Inc., to thrive.
Facebook agrees to sell a 1.6 percent stake to Microsoft for $240 million and forges advertising partnership.
Facebook unveils its "Beacon" program, a feature that broadcasts people's activities on dozens of outside sites. Yet another privacy backlash led Facebook to give people more control over "Beacon," before Facebook ultimately scrapped it as part of a legal settlement.
Facebook hires Sheryl Sandberg as chief operating officer, snatching the savvy, high-profile executive from Google Inc.
Facebook Chat is introduced.
Facebook introduces "Like," allowing people to endorse other people's posts. Four months later, Facebook surpasses News Corp.'s MySpace as the leading online social network in the U.S.
Facebook launches location feature, allowing people to share where they are with their friends and strangers.
Columbia Pictures releases "The Social Network," a movie about Zuckerberg and the legal battles over Facebook's founding. It gets eight Academy Awards nominations and wins three.
The Winklevoss twins end their legal battle over the idea behind Facebook. They had settled with Facebook for $65 million in 2008, but later sought more money.
Facebook introduces "Timeline," a new version of the profile page. It shows highlights from a person's entire Facebook life rather than recent posts.
Facebook agrees to settle federal charges that it violated users' privacy by getting people to share more information than they agreed to when they signed up to the site.
Facebook completes its move to Menlo Park, Calif. Its address is 1 Hacker Way.
Facebook begins making Timeline mandatory.
January 2012Facebook announced the limited beta release of Graph Search, a feature that will create a new way for people to navigate connections and search social networks.
Facebook files for an initial public offering (IPO) of stock. A few weeks later, it unveils new advertising opportunities for brands, allowing messages from them to mix in with Facebook status updates and photos.
Facebook announces plans to buy the photo-sharing mobile app Instagram for $1 billion in cash and stock.
Facebook sets a price range of $28 to $35 for its IPO.