In a surprise ceremony, Facebook CEO and founder Mark Zuckerberg married his longtime girlfriend, Priscilla Chan, in a private wedding at his home in Palo Alto California on Saturday.

Zuckerberg, who just became a billionaire and as a result of the Facebook IPO on Friday, reportedly placed a ring on his wife’s finger during the ceremony — a ring had what was described as a “simple ruby.”

Take a look at Zuckerberg’s personal page on Facebook, and you’ll see the above picture.

More on the way….

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The number of Americans who own smartphones rocketed past the number who own basic mobile phones this year, and marketers have been expanding their mobile budgets at a similarly rapid rate.

One study estimated mobile advertising will be $5.04 billion industry by 2015.

HighTable, a startup social website for professionals, compiled data about the key factors in the growing mobile marketing space in the infographic below.

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As Facebook rang the bell on Friday to become one of the largest publicly traded companies on the stock market, many critics continue to debate the staying power of the social network and how the IPO will impact the company’s future.

Earlier this week, a study from The Associated Press and CNBC surfaced that found nearly half of Americans believe that Facebook is a fad and will be replaced by competition in the future.

But is there already platform on the market that has the potential to truly replace Facebook? According to experts, no.

“The billion-dollar question is not if Facebook will be replaced, but when will it be replaced,” says Erik Qualman, author of the best-selling book, Socialnomics: How social media transforms the way we live and do business. “Their strongest competitive advantage today is their almost 1 billion global users and this creates a barrier to entry for other competitors.”

There’s no denying Facebook’s size and power. If Facebook were a country, it would be the third-largest behind China and India. Although some platforms such as Google Plus have some social features that Facebook doesn’t — including dynamic photo integration (Picasa), video (YouTube), mobile (Android) and contacts (Google Contacts)– if your family and friends don’t use Google Plus, it’s less appealing for you as a user.

“The two weakest points of Facebook’s current strategy revolve around mobile and social search,” Qualman says. “Facebook has been slow to try and capture the billions of dollars that Google captures via search. Search as we know it is ripe for disruption, yet Facebook has been slow to capitalize on developing a robust social search. There are no switching costs for people to move from one search engine to the next.”

Qualman also believes that Facebook will have to ramp up its mobile strategy to stay competitive.

SEE ALSO: Facebook CEO Mark Zuckerberg Rings The Opening Bell

“What could cause a potential downfall of the company is an inability to properly understand how to leverage mobile,” Qualman says. “Main competitors that could capitalize on this weakness could be Apple, Google or a company that hasn’t even been invented yet — but this is less likely since Facebook can buy most competition, such as the recent purchase of Instagram for $1 billion.”

“Zuckerberg is a smart guy, so he still has time to properly adjust,” Qualman adds.

Scott Campbell, an associate professor of communication studies at the University of Michigan, believes that Facebook’s streak will continue due to its adaptability. Over the years, the company has managed to stay relevant by incorporating the latest trends, from adding a new stream and Timeline to chat functionality and photo integration via Instagram.

“Facebook is always evolving,” Campbell said. “It is no longer just for maintaining personal ties. It has many civic and political uses as well, and has evolved to connect people to both the personal and public sphere of social life.”

However, Campbell cautions Facebook on its collection and use of personal information.

“It’s no secret that its privacy policy and settings have changed over time and can be confusing for many users,” he added. “Perceived or actual misuse of personal data is something that could hinder adoption rates and drive existing users away, so Facebook should be sensitive about that if it wants to avoid being just a fad.”

However, not everyone shares the sentiment that Facebook is here to stay, and investors are divided about whether the valuation of Facebook at more than $100 billion is too high. Many consumers also expressed the same concern on Twitter.

Sorry guys, I decided NOT to purchase Facebook… The valuation jumped to 108 Billion! Waaaaaaay too high

— Carl World Peace (@ItsMeCarlC) May 18, 2012

Analyst on BBC radio today said Facebook’s $100 billion value unrealistic given its $1 billion revenues. 1:100 ratio. Bubble could burst.

— Timothy Kalyegira (@TimKalyegira) May 18, 2012

What do you think? Will Facebook be around for years to come, and if not, what could replace it? Let us know your thoughts in the comments.

The Early Hours of Facebook HQ on IPO Day [PICS]

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Image courtesy of iStockphoto, Frankreporter.

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