The Online Publishers Association has released a white paper arguing that people who visit branded sites with original content are more active consumers that users of Yahoo and other large portals.

OPA found that its audiences, which comprise 74 percent of the online population, are more likely to purchase vehicles, make investments, improve their homes and buy electronics. They also are more active users of online video, an area of growing interest to advertisers. (The list of sites is on page 2 of the white paper; it includes the usual network, newspaper and magazine sites.

The study, which the portals will no doubt dispute, underscores the fierce competition developing for online advertising dollars, especially as companies continue to reduce spending on traditional media.

Even though branded sites and portals are dependent on one another for traffic and content, their relationship is changing. Advertisers will pay higher rates to be featured on original content than information available on other sites. Portals have added and will continue to add original content to meet this demand. That’s why branded sites are trying to convince marketers that they provided them the most value for their money.