Apple CEO Tim Cook on Monday courted the company’s largest market by opening a personal account on China’s most popular twitter-like microblogging site. His verified account on Weibo, operated by internet company Sina Corp, had garnered over 400,000 followers less than a day after it went online. The site has 176 million monthly active users as of the end of 2014. “Hello China! Happy to be back in Beijing, announcing innovative new environmental programs,” read the account’s first posting published on Monday afternoon. The launch of Cook’s blog coincided with his sixth visit to China this week, where the company said he would seek to expand renewable paper and energy initiatives. Apple said it is partnering with the World Wildlife Fund (WWF) to protect forests used in the production of paper packaging for Apple items, and it would increase its use of renewable energy in its factories in China. Cook’s debut on social media in China caught the attention of a number of top names in the Chinese technology world, including some of the domestic smartphone makers who compete directly with Apple. Lei Jun, chairman of fast-growing Xiaomi, and Deputy Senior Executive Yu Chengdong of Huawei Technologies both retweeted Cook’s post and said they welcome his visit. The two companies are second and third behind Apple in smartphone shipments in China. Huang Zhang, founder and chairman of Meizu, another domestic smartphone maker, commented “As a domestic manufacturer, we ought to learn from Apple in the aspect of environmental protection.” Some online users asked if there were any iPhone giveaways for reposting Cook’s comment, poking fun at a common approach used by domestic retailers to promote their products. User Tetek asked: “Guess who Cook will follow first on Weibo?”, then suggesting a slate of big names including Alibaba founder Jack Ma and ex-Google China chief Kai-fu Lee. China overtook the US as the largest market for the iPhone at the beginning of this year. In the past couple of months, Apple has also tapped into China’s second-hand market by introducing a scheme to buy used iPhones and iPads from customers and then repairing and reselling them. In Cook’s previous visits to China, he has met Premier Li Keqiang and visited China’s three major telecommunication operators as well as Apple factories.