"My day is not complete without checking my Facebook account," said Syaiful Anwar, a 47-year-old restaurant owner in Pekanbaru on Indonesia's Sumatra island. "To find out what is happening in this world, to bring together my friends and relatives (is) now just a click (of a) mouse away."
Indonesia has 65 million users who log in at least once a month. That's about a quarter of the country's population. India boasts another 93 million.
As Facebook's user base started growing in emerging markets, another hurdle emerged: the high cost of smartphones and Internet access. So, in 2011, Facebook launched an app called Facebook for Every Phone. It lets people without fancy smartphones access the most popular features, such as reading status updates and sharing photos. More than 100 million people use it each month.
Facebook is the first Internet experience for many people in India and other emerging markets, said Kevin D'Souza, Facebook's growth manager in India. That means people who have never used email are signing up for Facebook, using their phone numbers instead of an email address to log in.
"Facebook addresses a universal need," D'Souza said. "Everybody around the world wants to connect with people they care about."
Last summer, Facebook launched Internet.org, aimed at getting everyone in the world online.
"When I reflect on the last 10 years, one question I ask myself is: why were we the ones to build this? We were just students. We had way fewer resources than big companies. If they had focused on this problem, they could have done it," Zuckerberg wrote Tuesday. "The only answer I can think of is: we just cared more."
As far as birthdays go, Facebook's brought out reflection, nostalgia and lots of memories.
Connie Zong, who signed up for Facebook during her sophomore year at Harvard 10 years ago, remembers when she heard that Zuckerberg was dropping out of Harvard to work on Facebook.
"I remember thinking that guy is making such a big mistake," she said. "He's giving up a really great degree at a great university, and we're never going to hear from him again."
Associated Press writer Niniek Karmini in Indonesia and AP video journalist Priya Sridhar in Chicago contributed to this story.