Hong Kong (CNN) – China’s ‘Great Firewall’ keeps Chinese fans from following their favorite foreign stars on Twitter or Facebook, which are blocked in the mainland.

So more athletes and celebrities are jumping the fence.

Soccer star Cristiano Ronaldo is the latest to start his own Chinese microblogging site to build an online presence in the world’s second largest economy.

“Check out my photos form (sic) my 100^th game for Real Madrid,” Ronaldo’s latest “weibo” – Chinese for microblog – reads.

Ronaldo blogs for China’s Tencent Weibo, which has 233 million registered users according to its latest quarterly report. Its chief rival, Sina Weibo, said in its June quarterly report that in less than two years the microblogging site had surpassed 200 million users.

Ronaldo joins UK supergroup Radiohead and actor Tom Cruise as western stars who have reportedly started the equivalent of Twitter accounts in China in the past year.

Japanese porn star Sora Ai – whose films are technically banned in China – has 7 million followers on Sina Weibo.  The adult actress joined weibo after noticing the number Chinese followers on her Twitter account, causing wantchinatimes.com to note: “Clearly, not all Chinese netizens who leap the Great Firewall are political dissidents.”

The sheer market size of the China market is leading the push for foreign stars and athletes to go weibo: China has half a billion people now online – approaching twice as many netizens as there are U.S. citizens.

One stat alone tells the tale: On Sina Weibo, the NBA has more than 8 million fans. On Twitter? Just over 3 million.