Gannett Co.’s quarterly profit fell sharply as ad revenue came in much lower than a year earlier, when the Olympics and the presidential campaign gave a lift. Net income was $79.7 million, 40 percent lower than in the same period in 2012. Total revenue fell 4.3 percent to $1.3 billion. One of the few growth areas was the digital division, which grew 5.2 percent to $191 million. Circulation revenue was flat. In addition to its USA Today site, the company has 120 websites tied to local newspapers and television stations.