Buoyed significantly by the Beijing Olympics and the kick-off of football season, online sports destinations saw a 26% increase in unique visitors at work during August, according to New York-based Nielsen Online. The firm said that 42.3 million people visited the sites during the month, up from 33.4 million the prior year. A large chunk of that, more than 13.8 million visitors, went to the NBC Olympics website. "With broad interest in the Olympics, and the ramp up of the college and professional football seasons, August was a busy month for online sports fans," said Jon Gibs, the vice president of media analytics at Nielsen Online. Yahoo Sports was the top online sports destination at work in August, with 18.7 million unique visitors, growing 112 percent year-over-year. Web properties ESPN and FOX Sports on MSN also finished among the leaders.