The Internet Advertising Index will offer a snapshot of Web advertising by measuring monthly changes in the number of Web-site banners and button ads that a panel of about 15,000 home PC users download on pages they visit. With May as a base of 100, the June index rose to 103.9.
Over time, the index will offer another way to gauge growth in Internet advertising, and could be an early indicator about the relative strength or weakness of the market, said Manish Bhatia, VP-interactive services for Nielsen Media Research, which developed the index with partner NetRatings.
Nielsen/NetRatings' index will be reported monthly in Advertising Age.
"There's a lot of data out there for people to look at," Mr. Bhatia said. "A lot of people in this industry want a top-line snapshot."
Nielsen/NetRatings today also releases data showing the potency of big Web brands: The top 10 Web domains in June accounted for 55.7% of banner and button ads seen by home users, with Yahoo! delivering an astounding 25.4% of Internet ads. That figure includes Yahoo!'s self-promotions on its sites. The top 10 advertisers, meanwhile, accounted for 28.1% of ad impressions.
Nielsen/NetRatings is working on a similar ad index to cover Web use at work. Rival Media Metrix already tracks Web use in the office. NetRatings VP Marketing Tim Meadows said the company intends to develop work data-significant for finance, tech and business sites, and important for many consumer sites-but has