Facebook may be blocked in China but that hasn’t stopped the country rising to become the largest contributor of apps to the social network in Asia.

As we wrote last week, Facebook is aiming to recruit the cream of China’s graduate talent pool, but its footprint there is larger than may be expected. Speaking to Bloomberg, Facebook engineer David Lim revealed that China is the biggest contributor to Facebook’s partner network in Asia, with Chinese firms accounting for around 20 percent of those in the continent.

Facebook partners provide apps, games and other content that the social network’s 800 million plus users interact with, and it is the lure of this sizable audience that has encouraged Chinese firms to build content for the site.

Lim says that “developers in mainland China are important to us”, and Facebook made an effort to encourage more content when it set up a presence in Hong Kong in February 2011. The office is also used for sales and marketing as the company looks to increase advertising revenue from Chinese firms that want to reach an international audience.

Chinese social media sites, like Sina Weibo, are often referred to as a window into China for overseas marketers, and so, the other way round, Facebook is aiming to be an international channel for Chinese firms.

Facebook has made a sustained effort to grow its presence on the ground in Asia, with offices in Tokyo, Malaysia and Singapore, in addition to Hong Kong. However, unlike Google, it is yet to build a dedicated Asia data center in the region. Rumors of plans in Taiwan were denied by the company, which instead chose Sweden as the location for its first overseas data center.

Facebook has been blocked by China’s ‘Great Firewall’ Internet censorship policy since 2009 but it, Twitter and other outlawed websites can be accessed via a virtual private network (VPN), which uses Internet servers overseas to circumvent the censorship.

China has more than 500 million Internet users but, according to Facebook measurement service SocialBakers, there are little more than 400,000 Facebook users in the country. That figure ranks China as the social network’s 101st largest market, it is larger than Tanzania but smaller than Panama.