Online video ads are most effective when they run on magazine, newspaper or online news sites, rather than on portals or user-generated content sites, according to a study by the U.S. Online Publishers Association. The OPA found that more than one-third of consumers visiting media sites searched for more information after seeing a video ad, while only one-quarter did so after seeing an ad on a portal or user-generated video site. On local broadcast, national broadcast and cable TV sites, about 20% of consumers requested more information from a video ad. The study also showed that if consumers like the video content in an ad, their perception of the brand often becomes more positive.