Advertising that appears during the lunchtime and primetime dayparts yield the highest conversions - at midday, conversions are 35 percent higher than average - according to a study by aQuantive's Atlas Institute, reports ClickZ. The finding presents opportunities for both publishers and buyers, according to Young-Bean Song, director of analytics at Atlas. Publishers can charge more money for certain dayparts, while advertisers can pick the dayparts that suit them best.

The report cautioned advertisers that the extra cost of daypart targeting may offset the potential gain in acquisitions; on average, advertising in the lunchtime or evening daypart should not cost more than 35 percent higher than regular rates, it said.

"You will see conversion rates fluctuate through the day, but it's not happening in a vacuum," Song told ClickZ. "If you go full boar on this and cut out off hours, you may see increased efficiency, but you will sacrifice volume."