Chinese online and wireless media company Sina Corporation says its profit fell on higher costs as it announced its unaudited financial results for the first quarter ended March 31, 2011.

For the first quarter of 2011, Sina reported net revenues of USD100.2 million, compared to USD85.0 million for the same period last year. Of that total, advertising revenues grew 33% year over year to USD72.3 million, and non-advertising revenues decreased 9% year over year to USD27.9 million.

Net income attributable to Sina for the first quarter of 2011 was USD15.0 million, or USD0.23 diluted net income per share attributable to Sina. Non-GAAP net income attributable to Sina decreased 24% year over year to USD16.9 million, or USD0.25 non-GAAP diluted net income per share attributable to Sina.

"Sina's online advertising growth was strong in the first quarter, despite a high comparison basis from last year" stated Charles Chao, CEO of Sina, "The momentum for Weibo adoption is building across China. With the launch of the official Weibo.com, registered users for Weibo recently surpassed 140 million. We hope to ride this momentum and further expand Weibo's user base and user stickiness by significantly increasing our investment in the coming quarters."

Operating expenses for the first quarter of 2011 totaled USD41.8 million, compared to USD33.5 million for the same period last year. Operating income for the first quarter of 2011 was USD11.5 million, compared to USD14.6 million for the same period last year.

Sina estimates that its non-GAAP net revenues for the second quarter of 2011 will be between USD112 million and USD115 million, with advertising revenues to be between USD90 million and USD92 million and non-GAAP non-advertising revenues to be between USD22 million and USD23 million.