(Reuters) – Weibo Corp , the company behind Chinas biggest microblog by users, reported second-quarter revenue above analysts expectations, helped by a surge in advertising sales. The company, majority owned by Chinese internet firm Sina Corp , forecast third-quarter revenue between $79 million and $82 million. Analysts on average were expecting third-quarter revenue at $80.2 million, according to Thomson Reuters I/B/E/S. Weibo, which made its listing debut in the United States in April, said advertising and marketing revenue nearly doubled to $59.6 million in the second quarter ended June 30. Weibo, in which Chinas biggest e-commerce company Alibaba Group Holdings Ltd also has a stake, ended the quarter with 69.7 million daily active users.