Mobile "drives so much traffic" because many people start their day reading news on a phone or tablet, said Cindy Krum, chief executive at MobileMoxie, a mobile marketing consultancy.

Several new apps hope to capitalize on that by attracting news readers and the advertising dollars they bring.

Apple News, an app included in Apple's updated iOS 9 mobile operating system, launched last month, delivers content from more than 50 media partners, including the New York Times, Vanity Fair and Vogue.

Facebook launched its "Instant Articles" earlier this year in partnership with a number of media organizations to provide access to the news 10 times more quickly, through its social media infrastructure, than most news websites do.