Facebook co-founder and CEO Mark Zuckerberg wed longtime girlfriend Priscilla Chan at the weekend, announcing the nuptials through a status update on the social networking site.

The 28-year-old billionaire's wedding took place a day after Facebook's initial public offering on the Nasdaq stock exchange on Friday.

More than 280000 people "liked" Zuckerberg's status change, which was accompanied by a photo of the smiling couple in wedding attire in a small, verdant outdoor setting with a string of lights behind them.

The pair wed in an intimate backyard ceremony in Palo Alto, California, according to People magazine. They had been planning the exchange of vows for four months, but surprised their guests, who thought they were there to celebrate Chan's recent graduation from medical school, the magazine reported.

Zuckerberg's sister, Arielle Zuckerberg, posted, "Balls. Now I'm the only unmarried Zuckerberg ..." on her Facebook page. She is listed by Chan as a family member on the site.

Zuckerberg designed a simple ruby wedding ring for Chan himself, People reported. Guests dined on food from the couple's favourite restaurants, and nibbled on mouse-shaped chocolates that the pair ate on their first date nine years ago.

Tim Carvell, lead writer for The Daily Show with Jon Stewart, reacted to the news on Twitter, writing: "Congratulations, Mark Zuckerberg! As a gift, I got you the names of all my friends, a list of my favourite movies and some photos of me!"

Zuckerberg, whose shares are worth about $20-billion and who retains voting control of Facebook, marked the debut of his company's stock at Facebook's Silicon Valley campus on Friday, symbolically ringing the opening bell for stock trading.

The listing did not go as well as the social networking company had hoped, with shares closing just above the offering price of $38 a share after trading glitches and a last-minute, 25% increase in the number of shares being sold.

More than 576million shares changed hands, setting a trading volume record for US market debuts. Facebook posted $3.7-billion in revenue last year and $1-billion in profit. The site boasts 900million global users.

Facebook's emergence as a cultural phenomenon was depicted in the fictionalised 2010 film The Social Network.

Zuckerberg, Time magazine's Person of the Year in 2010, started Facebook in his Harvard University dorm room eight years ago, before dropping out of the Ivy League school.

Chan has just graduated from medical school at the University of California, San Francisco.

The couple met while they were both at Harvard. - Reuters