Yahoo CEO Marissa Mayer proclaimed Tuesday that her company's "future is mobile, and we are delivering mobile first." Yahoo reported a rise in second-quarter profits but a 1% dip in revenues from a year ago as the company continued a transition aimed at pulling in more wireless-driven sales. Without offering a comparison. Mayer said Yahoo attracts an average of 340 million mobile users a month. The company has pumped up its mobile-related workforce by eightfold, she added.