US online advertising revenue in 2006 was 35 percent higher than the previous year, according to an IAB (Interactive Advertising Bureau) official.

Ensuring publisher transparency, increasing advertising quality and embracing video are key to maintaining a strong US online advertising market, IAB officials have argued.

Marketers spent almost $17bn advertising on US websites in 2006, the fourth straight year of expansion for this market, the IAB said in a report issued yesterday.

"A 35 percent year-on-year growth is fantastic. We're very pleased," said Sheryl Draizen, the IAB's senior vice-president and general manager. She added that to continue the successful run, some things need to be improved, and opportunities must be seized.

For example, Draizen said, too many marketers fail to test their online adverts with the same stringency with which they test their ads for other media, such as television, radio and print publications.

This is a big mistake, because testing online ad campaigns before launching them is critical to ensure they are effective. Marketers often ignore the characteristics of a good online advert, she said.