Not long ago, China’s answer to Twitter was struggling: The microblog platform had lost ground to Tencent’s messaging service, WeChat, and China’s censors had begun forcing the closure of user accounts. But Weibo has shrugged off tough times to become a powerful outlet, not just for short posts but for long-form content such as news reports, film reviews, and videos. Second-­quarter revenue grew 68%, and the platform clocked 431 million monthly active users, up 19% year over year—all generating troves of data that Weibo is now monetizing.