SINA (Nasdaq: SINA) is reportedly getting ready to cash in on the booming popularity of its fast-growing microblogging site.

SINA's Weibo -- a site that is often described as China's Twitter, even though it's a closer fit to Tumblr or the new Google+ -- will roll out a virtual currency platform later this quarter, sources are telling Reuters.

Similar to Facebook Credits, Weibo's Weibi currency would be purchased with real money. The virtual funds would then be used to buy virtual trinkets, gifts, and app developer wares.

SINA hasn't made a concerted effort to monetize Weibo. It has simply relied on celebrities to take the free service viral. There are now an estimated 140 million Chinese people using Weibo, so it's probably a good time for SINA to find ways to cash in on the heavy traffic.

Paying up for virtual goods may have seemed ludicrous a couple of years ago, but the popularity of Zynga's casual games -- where virtual purchases make games including FarmVille more enjoyable -- have started to take off. Die-hard gamers in China are already familiar with online gaming companies that incorporate virtual goods in their multiplayer fantasy games, so it's not as if SINA will have to necessarily educate the market.

Social networking is still a wild card in China, largely as a result of the country's restrictive government. There are social sites, of course. Weibo competes with Renren (NYSE: RENN), Tencent, and several smaller players for attention. Baidu (Nasdaq: BIDU) and Facebook are rumored to be working on a way to break Facebook into China. If SINA is successful in expanding the monetization of social networking, you can be sure that other sites will follow.

China's just getting started, really. Growth through virtual currency is virtually certain.

Are you comfortable with Chinese stocks in your portfolio? Share your perspective in the comment box below.