Online readership of U.S. newspapers has gone up by 10 percent in the first quarter, according to a Nielsen study, commissioned by the Newspaper Association of America, The Wall Street Journal reported.

The study found that more than 73.3 million unique monthly visitors viewed online newspaper editions in the first three months of the year, an increase from 66.4 million the same time last year.

However, the increase in readership does not translate to more revenue, Dave Gusse, president of NSA Media, pointed out in an e-mail to the WSJ saying, "advertisers are not willing to pay for premium content." Gusse explained that the problem was that "online offers hundreds if not thousands of outlets in every market in every country, which makes it a buyer's market."

The National Association of Newspapers sees the study's findings as encouraging to advertisers, showing that more than 28 percent of the participants in the study with a total income of over US$100,000 claimed to have visited an online newspaper's site in the last week, with approximately 83 percent of that group saying they read either a print or online edition of a paper in the last seven days.

The study follows the findings of another Nielsen survey, which showed a high growth rate in online videos and social media sites.