New York--Online advertising revenue totaled $6.01 billion in 2002, down 15.8% from 2001 revenues of $7.13 billion, according to the Internet Ad Revenue Report, an annual study conducted by the New Media Group at PricewaterhouseCoopers in conjunction with The Interactive Advertising Bureau. Revenue for the fourth quarter of 2002 increased 6.7% from a year earlier, to $1.6 billion. Keyword search was the lead indicator of growth for the industry, according to the study. It represented 15% of ad revenues in 2002, more than triple its share in 2001. In the fourth quarter, it garnered 21% of total revenues.