Baidu.com China’s leading search engine, and a member of our domain stock parking index, second-quarter profit soared 87 percent over the year-earlier period on rapid growth in revenue from smaller advertisers.

Net income for the quarter ending June 30 was 265 million yuan ($38.6 million), or 7.62 yuan ($1.11) per share, on revenue of 802.6 million yuan ($117 million), the company said. Revenue was double that of the same quarter in 2007.

Baidu said the rise in revenue came from growth in the number of marketing customers and revenue per customer.

Baidu, based in Beijing, has more than 60 percent of China’s Internet search market, well ahead of second-place Google Inc.

China’s population of Internet users tied the United States for the world’s largest in February with 221 million people online, according to the government.

The industry still lags the United States, South Korea and other markets in financial terms. But incomes are rising rapidly and the number of Chinese online is expected to expand by double digits annually in coming years while other major markets grow more slowly.

China’s total second-quarter search revenue was 1.2 billion yuan ($175 million), the research firm Analysys International reported this week. It forecast growth of more than 30 percent a year, with total revenue reaching 137.5 billion yuan in 2010.

Baidu cautioned that it expects its revenue growth rate in the coming quarter to fall to 13-16 percent due to temporary changes in customer behavior during August’s Beijing Olympics.