Compared to six years ago, U.S. Internet users are spending more time on content, according to the new data, Internet Activity Index, by the Online Publishers Association. The increase has come from communication and commerce sites, Media Post reported.

The Internet Activity Index was introduced in 2003, which tracks Internet usage on a monthly basis, across five categories: commerce, communications, community, content and search.

In 2009, an average user spent 42 percent of their time online on content sites versus 34 percent in 2003, while the actual amount of time spent on content has almost doubled since 2003, up from three hours and 42 minutes to six hours and 58 minutes, Media Post reported.

By contrast, people spent less time on communication online properties, such as Yahoo Mail, AOL Instant Messenger and MSN Groups, down from 46 percent of online time, or five hours and 20 minutes, in 2003 to 27 percent, or four hours and 54 minutes in 2009.

The share of time spent on commerce sites also dropped, from 16 percent to 13 percent, but the actual time actually gained 26 percent from two hours and seven minutes to two hours and 40 minutes. According to OPA, one reason for the shrinking time spent on communication and commerce has been the rise of social networking sites in recent years.

"In 2008, we introduced the Community category based on the emergence and popularity of sites like Facebook, MySpace and LinkedIn," said OPA President Pam Horan. "These new sites have had significant impact on the communications category, which saw a 41 percent decline, due to the fact consumers are using community sites where they can conduct these same activities more efficiently."

In 2009, community sites contributed 13 percent of online time, or three hours and one minute on average per person each month. Meanwhile, time spent on search has doubled from 27 minutes to 54 minutes, but the share only been up a little from 3 percent to 5 percent, Media Post reported.