Shares of Facebook (META -0.52%) soared today, and it's all about mobile monetization.

"I believe that over the long run we're going to see more monetization per time spent on mobile than on desktop," CEO Mark Zuckerberg said during last night's call, sparking a rally in companies where mobile migration away from traditional PC usage was seen as a disadvantage.

Zuckerberg laid out the bullish case. Mobile means more interaction. Just 40% of Facebook's active users on desktop clients alone visit the site on any given day, but 70% of smartphone owners are firing up the app on any given day.

The challenge, of course, has been to find a way to milk some money out of mobile users. Smaller screens make it impractical to wedge a column of ads on the right the way that the leading social networking website does on desktops.

"Mobile is a forcing function for us to rethink these experiences to be in mind," Zuckerberg said, stressing deeper mobile integration across all of his product groups. "This is already unlocking a lot of ideas and creativity, and we're starting to see higher-quality monetization experiences in terms of better ad products for people and better results for advertisers."

It's not just talk. Facebook wasn't even monetizing mobile usage a year ago, and now it's generating nearly $2 million a day.

This brings us to China. Facebook still lacks a formal and legal presence in the world's most populous nation, but it's a country full of cell phone users. Its largest carrier -- China Mobile (CHL) -- recently disclosed that it has 698.5 million customers as of the end of last month. Sure, most of those accounts are on old-school feature phones, but anyone that has seen China lining up for iPhone rollouts or the latest Android devices knows that the country is warming up to smartphones quickly.

This has naturally been seen as a challenge for Renren (RENN), China's largest social networking website operator, and SINA (SINA). SINA Weibo is considered the Twitter of China, and both companies are hoping that there's some serious money to be made in monetizing mobile.

SINA recently began placing ads on its Weibo micro-blogging website. Wedging sponsored spots into news feeds is a similar strategy that Facebook and Twitter are incorporating closer to home. Renren has even more to prove. Analysts don't see it turning a profit until 2014 at the earliest, and it will generate as much revenue for all of 2012 as Facebook does in less than two weeks. However, if mobile does become the immersive and engaging platform that Zuckerberg thinks it will be, SINA, Renren, and the suddenly mobile-focused search engine giant Baidu (NASDAQ: BIDU) will become big winners as companies that are already magnetic attractions for China's growing base of smartphone users.