The Interactive Advertising Bureau, an industry group, conducted the quarterly study with PricewaterhouseCoopers.About half of the ad revenue, $14.8 billion, came from the search category. Those are the text-based ads that are sold by Google and others and that are targeted to search terms and other keywords. ___ By The Associated Press(equals) The Dow Jones industrial average fell 82.79 points to 13,032.75. The Standard & Poor's 500 fell 5.64 points to 1,385.14 and the Nasdaq composite index fell 11.37 points to 3,031.45. Benchmark West Texas Intermediate crude fell $1.53 to finish at $102.67 per barrel in New York, while Brent crude lost 81 cents to end at $117.97 per barrel in London. In other energy trading, heating oil gave up less than a penny to finish at $3.1182 per gallon and gasoline futures lost 3.13 cents to end at $3.2027 per gallon. Natural gas futures were unchanged at $1.9510 per 1,000 cubic feet.