Eighty percent of Baidu Inc's (NASDAQ: BIDU) revenues come from small and midsized businesses who spend just ¥15,000 ($1 = ¥6.8) a year on average to have their information shown on the largest Chinese search engine, said Baidu public relations officer Zhu Guang at an online marketing seminar over the weekend. He said some 300,000 small customers contributed ¥4.5 billion to the company's total takings in 2009, when the Chinese online ad market was worth ¥20.7 billion. The market is projected to hit ¥30 billion this year and ¥100 billion by 2013.