Sina Weibo, a Twitter-like microblog service, on Thursday announced that it had about 140 million registered users at the end of April, up from 100 million at the end of February.

Sina estimates that its microblog service will have more than 200 million registered users by the end of this year, said Cao Guowei, or Charles Chao, president and chief executive officer of Sina, at a press conference for its quarterly report.

The company will invest heavily in the microblog this year, about 100 million U.S. dollars more than last year, Cao said.

The company will also focus on improving the functions of Sina Weibo to integrate online gaming and e-commerce platforms, Cao said.

Sina Weibo was launched on Aug. 28, 2009 and had 50 million registered users by the end of October 2010.

Sina's shares dropped 0.24 percent to 119.80 U.S. dollars per share on Nasdaq before these results were released.