Facebook History: 10 Defining Moments

In 2004, George W. Bush was reelected to office, Britney Spears was married (twice), and a 19-year-old Harvard University sophomore launched a website from his dorm that would change the way we communicate.

Ten years ago, Mark Zuckerberg called it "Thefacebook." Today, it's just "Facebook" -- a social network that more than 1.23 billion people love, loathe, and love to loathe.

As Facebook celebrates its 10th birthday Tuesday, here's a look back at the decisions and milestones that shaped the social network.

[Get a grip on your Facebook account. Read 10 Most Misunderstood Facebook Privacy Facts.]

1. Zuckerberg releases Facemash

Without Facemash there may be no Facebook.

In October 2003, Zuckerberg and three of his classmates -- Andrew McCollum, Chris Hughes, and Dustin Moskovitz -- launched a website that let visitors compare two student pictures and determine which one was better looking than the other. To populate the website, Zuckerberg hacked the "facebooks" that Harvard maintained to help students identify each other, according to Harvard's student newspaper, The Crimson.

A few days after launching Facemash, Harvard executives shut it down and Zuckerberg faced charges of violating copyrights, breach of security, and violating individual privacy -- issues he would become all too familiar with in years to come.

Shortly thereafter, Zuckerberg began writing code for what would later become known as "thefacebook."

2. Thefacebook launches

On Feb. 4, 2004, thefacebook.com launched. Within 24 hours, the website grew to between 1,200 and 1,500 users, according to Moskovitz. In the first month, more than half of Harvard's undergraduates signed up. Soon after, Zuckerberg and team opened registration to fellow Ivy League schools and Boston-area colleges and universities.

3. Facebook adds photos

Can you imagine Facebook without selfies, babies, or photos of food? In October 2005, the social network gave its users -- then, just college students -- unlimited storage to upload images.

Today, photos remain one of Facebook's most popular features. In September 2013, the social network announced that users have uploaded more than 250 billion photos. More than 350 million are uploaded every day.

4. Facebook lets anyone join

Facebook continued expanding as its network grew to thousands of colleges, universities, and high schools worldwide. Then on September 26, 2006, the social network opened its doors to everyone, even parents and grandparents, a move that would horrify teens and young adults -- and set the tone for a period of unprecedented growth. Facebook closed 2006 with 12 million users, up from 5.5 million the year before.

5. Facebook rejects Yahoo offer

In September 2006, after dismissing a number of suitors, Facebook entertained Yahoo's $1 billion offer for purchase. Peter Thiel, Facebook's first investor and board member, recalled the meeting 22-year-old Zuckerberg held to discuss the offer:

"Both [Facebook board member Jim Bryer] and myself on balance thought we probably should take the money. But Zuckerberg started the meeting like, 'This is kind of a formality, just a quick board meeting, it shouldn't take more than 10 minutes. We're obviously not going to sell here.' "

Thiel said money never motivated Zuckerberg. He recalled him saying: "I don't know what I could do with the money. I'd just start another social networking site. I kind of like the one I already have."

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