Chinese online search platform Baidu (BIDU.NASDAQ, B1C.FRA) reported a net profit increase of 36% in the fourth quarter, as its revenue surged 42% to US$1.02 billion (RMB6.335 billion), The Wall Street Journal reported. Baidu made a profit of US$448.7 million, increasing from US$328.72 million in the same period the previous year. However, analysts are concerned about the company’s future profitability as Baidu’s share of the search market stagnates and costs rise. Expenses increased 52% year-on-year to US$127.2 million in the fourth quarter. R&D expenses surged 70% year-on-year, as the company invested in mobile services, which could take a number of years to become profitable.