Even though Facebook has been banned in China since 2009, Chinese developers are still producing software for the social networking giant. And with this, Facebook has been able to portray an idea of potential growth in China for potential investors.

David Lim, a Facebook mobile developer relations division engineer, recently told Bloomberg that China makes up roughly 20% of its partner network in Asia, with Chinese developers targeting overseas users. Lim adds, “we now have Chinese-language help pages for developers, and we are working on giving them better support. Developers in mainland China are important to us.”

China had 513 million internet users at the end of 2011, more than the population of the U.S. and Japan combined, but sites like Facebook, Twitter and Google + are banned in that country. Internet pornography, gambling and anti-communist sentiment are also not permitted, and China expects locals governments to monitor and censor the web use regarding correlating locales. As Facebook filed its initial public offering, the comment on China was, “users are generally restricted from accessing Facebook from China. We do not know if we will be able to find an approach to managing content and information that will be acceptable to us and to the Chinese government.”

Still, Shanda Games Ltd., the third largest online games company in China, is developing titles for Facebook users, according to Shanda CEO Alan Tan.

So, in China, users can access a fake Facebook called renren, all the while developing apps for the real Facebook, and then “weib” about it on the fake Twitter.