Sales through online adverts are booming, according to a recent U.S. study. In a 40 percent raise from the same time last year, Sales hit $4.6 billion in the first half of 2004. Paid search ads did the best, where ads linked to results in Google, Yahoo, MSN and other portals brought in revenue of $947 million in the quarter, almost double on the same period in the previous year. The increases mark the industry's seventh consecutive quarter of positive results. Such success is welcome in the world since the dot-com burst.