BEIJING - A senior Chinese propaganda official has said real-name registration for the nation’s hugely popular microblogs will be expanded, as authorities tighten their grip on the web amid fear of unrest. Beijing, Shanghai and the southern province of Guangdong have recently ordered new users of weibos — microblogs similar to Twitter — to register using their real names, making it easier for authorities to track them. “This started at the end of last year. At first it applies to new users only, and it will then be expanded to existing users,” said Wang Chen, the minister in charge of the press office of the State Council — China’s cabinet. He told reporters weibos had exploded in popularity, with hundreds of millions of loyal users who wrote around 150 million postings every day.