Despite being blocked in China, Twitter (TWTR.N) is courting Chinese companies to buy advertising space on its service used by more than 300 million people elsewhere in the world. “It’s not a coincidence that we are here now,” Peter Greenberger, director of sales for emerging markets at Twitter, told Reuters on Tuesday. The San Francisco-based company already works with Chinese smartphone maker Xiaomi, online shopping giant Alibaba Group (BABA.N), white goods producer Qingdao Haier and flag carrier Air China to target customers abroad.