Internet users spend almost half their time online reading and watching content, dwarfing the time spent searching for information, communicating with others and buying products, according to a four-year analysis of Internet activity released Monday.

The new study from the US-based Online Publishers Association (OPA) found that the time Internet users spend viewing online content is up 37 percent from four years ago.

The study analyzes four years of data compiled in the association's Internet Activity Index (IAI), a monthly measure of online e-commerce, communications, search and content activity done by Nielsen/NetRatings.

While users in 2003 spent 46 percent of their time online communicating, they now spend 47 percent of their time viewing content, according to the study. Time spent using e-mail or instant messaging tools has dropped 28 percent over the last four years, while the time spent on e-commerce activities is down 5 percent over the same period. Users spend about 5 percent of their time online searching for data.

Pam Horan, president of the OPA, noted that the June decision by Nielsen/NetRatings to measure Web activity using a "total minutes" metric is a valuable supplement to other Web use analysis.

"The IAI has identified a very significant and sustained trend in where consumers are spending their online time," Horan said in a statement. "The index indicates that, over the last four years, the primary role of the Internet has shifted from communications to content."

The growing popularity of social networking sites with a heavy focus on content is helping to drive the shift toward spending more time with content, according to Horan. According to publishers group, other factors behind the changes include the following:

• A faster Internet.
• The increased popularity of online video.
• Improvements in search tools, which are helping users find content more easily.
• The large increase of the amount of content on the Web.
• The increased use of instant messaging, which has led to a reduction in the time spent on communication activities.