Microblogging website Twitter has gained much interest in the investing community over the past few months as social websites like Facebook and Groupon have seen their valuations soar.

This week, the notoriety grew even greater as news leaked that the privately held Twitter has been in talks with Google (Nasdaq: GOOG) and Facebook about a possible acquisition valuing the company at up to $10 billion. That is pretty good for a company that had revenue of less than $50 million in 2010 and has still not figured out how it was going to become profitable.

Is an unprofitable Twitter actually worth $10 billion? I suppose it is if that is what the market is willing to pay for it, but I would be a lot more confident if it had access to the largest Internet market in the world -- China. That is why many investors who believe that microblogging can be monetized before another hot trend comes along are turning to China's fourth most visited website SINA (Nasdaq: SINA).

SINA is one of the original Chinese Web-portal sites along with Sohu.com (Nasdaq: SOHU) and NetEase.com (Nasdaq: NTES) to survive the dot-com bubble and become leaders in the fastest-growing Internet market in the world. Sohu and NetEase.com broadened their scope through popular online gaming sites, while SINA became the largest Yahoo!-like Web-portal in China. Today though, SINA is drawing interest for its leadership in the social networking space with its Weibo microblogging service. The site's popularity is growing rapidly and is evolving into a potentially more lucrative Chinese hybrid of Twitter and Facebook. The growth potential is no doubt enormous, but so is the risk for a business that depends on transparency and freedom of speech, which is something that China still does not provide. Censorship is what allowed Weibo to become the social networking leader in China, but it could also be its downfall.

A restricted social network
Frankly, I'm really not concerned with how big Weibo can become. China already has more Internet users than any country in the world, and about two-thirds of the entire population doesn't even use the Internet yet. According to Piper Jaffray, SINA has more than 50 million users less than two years after it was started, and it is adding about 10 million users a month. Additionally, Weibo already commands nearly 90% of the Chinese microblogging business. However, I am concerned with how big the Chinese government will allow this network to grow.

Let's not forget that if the Chinese government didn't throw out Twitter and Facebook I most likely wouldn't be writing this article. So could the government shut down Weibo as well? I wouldn't put it out of the realm of possibility. Certainly it would be a hit to China's credibility globally, but in this regard China has shown a penchant for impassiveness. Weibo is already highly censored, and "sensitive" posts are deleted by law. For example, New York Times columnist Nicholas Kristof had his Weibo account deleted after making just five posts on the site. During the recent protests in Egypt, if a Weibo user attempted to search for content related to the uprising, users were sent to a page that explained that it was legally restricted from showing these search results.

China has also seen demonstrations and protests of late, though certainly not to the extent of Egypt and Libya, as its rising middle class pushes for more rights and less censorship. This weekend, anonymous users on Weibo attempted to start protests referred to as a "Jasmine Revolution" in major cities in China, but before the word spread, any reference or search for these words was deleted. As a result, Chinese President Hu Jintao called for even tighter Internet censorship to prevent "social unrest."

Social networking site LinkedIn was also blocked for more than 24 hours, in light of a pro-democracy campaign on the site -- a movement that was started by a user named "Jazmine Z" pushing for less government censorship in China.

SINA must play nice
SINA management knows the importance of playing nice with a Chinese government that can shut down Weibo at its discretion, or possibly start its own competing site. Chinese search leader Baidu (Nasdaq: BIDU) learned the same lesson this week, as China's government news agency teamed up with government-owned China Mobile (NYSE: CHL) to launch Panguso.com. In its present form, the search engine is no match for Baidu's Web prowess, but it serves as a nice reminder that it is probably in the company's best interest to continue to abide strictly to the government's censorship rules.

SINA has proven to be a very well-run and important Chinese company, and the stock warrants a look just based on its core portal business. However, much of the 100% run-up since July in its share price can be attributed to the emergence and rapid growth of Weibo, which I believe is a dangerous proposition. As we have witnessed over the past month, the risk of "social unrest" is real. What this means for social networks in China is anyone's guess, but after the run SINA has had I think the risk/reward is not in investors favor.

Andrew Bond owns no shares in the companies listed. SINA is a Motley Fool Stock Advisor pick. Google is a Motley Fool Inside Value choice. Baidu, Google, Sohu.com, and NetEase.com are Motley Fool Rule Breakers selections. The Fool owns shares of China Mobile and Google. You can follow Andrew on Twitter @Bond0 or on his RSS feed. Try any of our Foolish newsletter services free for 30 days. The Fool has a disclosure policy.