U.S. stocks ended the week narrowly mixed with investors on the sidelines ahead of next week's critical jobs report. Crude oil also erased earlier gains after the latest weekly read on active oil rigs in the U.S. fueled fears domestic supply isn't falling as fast as hoped. Oprah lost roughly $42 million on Friday on her investment in Weight Watchers (WTW). The weight-loss company reported an unexpected loss in its fourth quarter. Sales have declined for twelve straight quarters. Shares of Baidu (BIDU) climbed after reporting a 33% increase in quarterly sales, driven by growth in demand for mobile. Mobile advertising revenue made up more than half of total sales in the recent quarter. TheStreet's Keris Lahiff has details from Wall Street.